diff --git a/Platform/RecursiveLock.swift b/Platform/RecursiveLock.swift
index 10b9bbb0b..b7363105d 100644
--- a/Platform/RecursiveLock.swift
+++ b/Platform/RecursiveLock.swift
@@ -9,7 +9,7 @@
 import Foundation
 
 #if TRACE_RESOURCES
-    class RecursiveLock: NSRecursiveLock {
+    class RecursiveLock: NSRecursiveLock, @unchecked Sendable {
         override init() {
             _ = Resources.incrementTotal()
             super.init()
diff --git a/Rx.playground/Sources/SupportCode.swift b/Rx.playground/Sources/SupportCode.swift
index 849a79f18..e9b6d2060 100644
--- a/Rx.playground/Sources/SupportCode.swift
+++ b/Rx.playground/Sources/SupportCode.swift
@@ -24,7 +24,7 @@ public enum TestError: Swift.Error {
  - parameter delay: time in seconds to wait before executing `closure`
  - parameter closure: `Void` closure
  */
-public func delay(_ delay: Double, closure: @escaping () -> Void) {
+public func delay(_ delay: Double, closure: @escaping @Sendable () -> Void) {
 
     DispatchQueue.main.asyncAfter(deadline: .now() + delay) {
         closure()
diff --git a/RxBlocking/BlockingObservable+Operators.swift b/RxBlocking/BlockingObservable+Operators.swift
index 02104a25d..243c68c42 100644
--- a/RxBlocking/BlockingObservable+Operators.swift
+++ b/RxBlocking/BlockingObservable+Operators.swift
@@ -73,7 +73,7 @@ extension BlockingObservable {
     ///
     /// - parameter predicate: A function to test each source element for a condition.
     /// - returns: Returns the only element of an sequence that satisfies the condition in the predicate, and reports an error if there is not exactly one element in the sequence.
-    public func single(_ predicate: @escaping (Element) throws -> Bool) throws -> Element {
+    public func single(_ predicate: @escaping @Sendable (Element) throws -> Bool) throws -> Element {
         let results = self.materializeResult(max: 2, predicate: predicate)
         let elements = try self.elementsOrThrow(results)
 
@@ -101,9 +101,9 @@ extension BlockingObservable {
 }
 
 extension BlockingObservable {
-    private func materializeResult(max: Int? = nil, predicate: @escaping (Element) throws -> Bool = { _ in true }) -> MaterializedSequenceResult<Element> {
-        var elements = [Element]()
-        var error: Swift.Error?
+    private func materializeResult(max: Int? = nil, predicate: @escaping @Sendable (Element) throws -> Bool = { _ in true }) -> MaterializedSequenceResult<Element> {
+        nonisolated(unsafe) var elements = [Element]()
+        nonisolated(unsafe) var error: Swift.Error?
         
         let lock = RunLoopLock(timeout: self.timeout)
         
@@ -114,7 +114,7 @@ extension BlockingObservable {
         }
         
         lock.dispatch {
-            let subscription = self.source.subscribe { event in
+            let subscription = self.source.subscribe { @Sendable event in
                 if d.isDisposed {
                     return
                 }
diff --git a/RxBlocking/RunLoopLock.swift b/RxBlocking/RunLoopLock.swift
index cc8c9e00d..242aeaa74 100644
--- a/RxBlocking/RunLoopLock.swift
+++ b/RxBlocking/RunLoopLock.swift
@@ -31,7 +31,7 @@ final class RunLoopLock {
         self.currentRunLoop = CFRunLoopGetCurrent()
     }
 
-    func dispatch(_ action: @escaping () -> Void) {
+    func dispatch(_ action: @escaping @Sendable () -> Void) {
         CFRunLoopPerformBlock(self.currentRunLoop, runLoopModeRaw) {
             if CurrentThreadScheduler.isScheduleRequired {
                 _ = CurrentThreadScheduler.instance.schedule(()) { _ in
diff --git a/RxCocoa/Common/ControlTarget.swift b/RxCocoa/Common/ControlTarget.swift
index b09d5c72b..073458b1a 100644
--- a/RxCocoa/Common/ControlTarget.swift
+++ b/RxCocoa/Common/ControlTarget.swift
@@ -21,8 +21,9 @@ import RxSwift
 #endif
 
 // This should be only used from `MainScheduler`
-final class ControlTarget: RxTarget {
-    typealias Callback = (Control) -> Void
+@MainActor
+final class ControlTarget: RxTarget, @unchecked Sendable {
+    typealias Callback = @Sendable @MainActor (Control) -> Void
 
     let selector: Selector = #selector(ControlTarget.eventHandler(_:))
 
@@ -72,16 +73,23 @@ final class ControlTarget: RxTarget {
             callback(control)
         }
     }
-
+    
+    @Sendable
     override func dispose() {
         super.dispose()
 #if os(iOS) || os(tvOS) || os(visionOS)
-        self.control?.removeTarget(self, action: self.selector, for: self.controlEvents)
+        MainScheduler.assumeMainActor(execute: {        
+            self.control?.removeTarget(self, action: self.selector, for: self.controlEvents)
+        })
 #elseif os(macOS)
-        self.control?.target = nil
-        self.control?.action = nil
+        MainScheduler.assumeMainActor(execute: {
+            self.control?.target = nil
+            self.control?.action = nil
+        })
 #endif
-        self.callback = nil
+        MainScheduler.assumeMainActor(execute: {
+            self.callback = nil
+        })
     }
 }
 
diff --git a/RxCocoa/Common/DelegateProxy.swift b/RxCocoa/Common/DelegateProxy.swift
index d103448e7..55889438d 100644
--- a/RxCocoa/Common/DelegateProxy.swift
+++ b/RxCocoa/Common/DelegateProxy.swift
@@ -266,7 +266,7 @@
         fileprivate let selector: Selector
 
         init<P, D>(selector: Selector, delegateProxy _delegateProxy: DelegateProxy<P, D>) {
-            weak var weakDelegateProxy = _delegateProxy
+            nonisolated(unsafe) weak var weakDelegateProxy = _delegateProxy
 
             let dispatcher = PublishSubject<[Any]>()
             self.dispatcher = dispatcher
diff --git a/RxCocoa/Common/DelegateProxyType.swift b/RxCocoa/Common/DelegateProxyType.swift
index 0e7448a54..32eecca9f 100644
--- a/RxCocoa/Common/DelegateProxyType.swift
+++ b/RxCocoa/Common/DelegateProxyType.swift
@@ -151,7 +151,7 @@ extension DelegateProxyType {
     /// When make 'Rx*DelegateProxy' subclass, call 'Rx*DelegateProxySubclass.register(for:_)' 1 time, or use it in DelegateProxyFactory
     /// 'Rx*DelegateProxy' can have one subclass implementation per concrete ParentObject type.
     /// Should call it from concrete DelegateProxy type, not generic.
-    public static func register<Parent>(make: @escaping (Parent) -> Self) {
+    public static func register<Parent>(make: @escaping @Sendable (Parent) -> Self) {
         self.factory.extend(make: make)
     }
 
@@ -214,7 +214,7 @@ extension DelegateProxyType {
     /// - parameter onProxyForObject: Object that has `delegate` property.
     /// - returns: Disposable object that can be used to clear forward delegate.
     public static func installForwardDelegate(_ forwardDelegate: Delegate, retainDelegate: Bool, onProxyForObject object: ParentObject) -> Disposable {
-        weak var weakForwardDelegate: AnyObject? = forwardDelegate as AnyObject
+        nonisolated(unsafe) weak var weakForwardDelegate: AnyObject? = forwardDelegate as AnyObject
         let proxy = self.proxy(for: object)
 
         assert(proxy._forwardToDelegate() === nil, "This is a feature to warn you that there is already a delegate (or data source) set somewhere previously. The action you are trying to perform will clear that delegate (data source) and that means that some of your features that depend on that delegate (data source) being set will likely stop working.\n" +
@@ -317,7 +317,7 @@ extension DelegateProxyType where ParentObject: HasPrefetchDataSource, Self.Dele
         import UIKit
 
         extension ObservableType {
-            func subscribeProxyDataSource<DelegateProxy: DelegateProxyType>(ofObject object: DelegateProxy.ParentObject, dataSource: DelegateProxy.Delegate, retainDataSource: Bool, binding: @escaping (DelegateProxy, Event<Element>) -> Void)
+            func subscribeProxyDataSource<DelegateProxy: DelegateProxyType>(ofObject object: DelegateProxy.ParentObject, dataSource: DelegateProxy.Delegate, retainDataSource: Bool, binding: @escaping @Sendable (DelegateProxy, Event<Element>) -> Void)
                 -> Disposable
                 where DelegateProxy.ParentObject: UIView
                 , DelegateProxy.Delegate: AnyObject {
@@ -360,10 +360,11 @@ extension DelegateProxyType where ParentObject: HasPrefetchDataSource, Self.Dele
                     
                 return Disposables.create { [weak object] in
                     subscription.dispose()
-
-                    if object?.window != nil {
-                        object?.layoutIfNeeded()
-                    }
+                    MainScheduler.assumeMainActor(execute: {
+                        if object?.window != nil {
+                            object?.layoutIfNeeded()
+                        }
+                    })
 
                     unregisterDelegate.dispose()
                 }
@@ -410,7 +411,7 @@ extension DelegateProxyType where ParentObject: HasPrefetchDataSource, Self.Dele
             self._identifier = proxyType.identifier
         }
 
-        fileprivate func extend<DelegateProxy: DelegateProxyType, ParentObject>(make: @escaping (ParentObject) -> DelegateProxy) {
+        fileprivate func extend<DelegateProxy: DelegateProxyType, ParentObject>(make: @escaping @Sendable (ParentObject) -> DelegateProxy) {
                 MainScheduler.ensureRunningOnMainThread()
                 precondition(self._identifier == DelegateProxy.identifier, "Delegate proxy has inconsistent identifier")
                 guard self._factories[ObjectIdentifier(ParentObject.self)] == nil else {
diff --git a/RxCocoa/Common/Infallible+Bind.swift b/RxCocoa/Common/Infallible+Bind.swift
index 4849641a4..f9c1524ed 100644
--- a/RxCocoa/Common/Infallible+Bind.swift
+++ b/RxCocoa/Common/Infallible+Bind.swift
@@ -70,7 +70,7 @@ extension InfallibleType {
     - parameter onNext: Action to invoke for each element in the observable sequence.
     - returns: Subscription object used to unsubscribe from the observable sequence.
     */
-    public func bind(onNext: @escaping (Element) -> Void) -> Disposable {
+    public func bind(onNext: @escaping @Sendable (Element) -> Void) -> Disposable {
         self.subscribe(onNext: onNext)
     }
 
diff --git a/RxCocoa/Common/Observable+Bind.swift b/RxCocoa/Common/Observable+Bind.swift
index 500154aaa..2ff6f1318 100644
--- a/RxCocoa/Common/Observable+Bind.swift
+++ b/RxCocoa/Common/Observable+Bind.swift
@@ -75,7 +75,7 @@ extension ObservableType {
     */
     public func bind<Object: AnyObject>(
         with object: Object,
-        onNext: @escaping (Object, Element) -> Void
+        onNext: @escaping @Sendable (Object, Element) -> Void
     ) -> Disposable {
         self.subscribe(onNext: { [weak object] in
             guard let object = object else { return }
@@ -94,7 +94,7 @@ extension ObservableType {
     - parameter onNext: Action to invoke for each element in the observable sequence.
     - returns: Subscription object used to unsubscribe from the observable sequence.
     */
-    public func bind(onNext: @escaping (Element) -> Void) -> Disposable {
+    public func bind(onNext: @escaping @Sendable (Element) -> Void) -> Disposable {
         self.subscribe(onNext: onNext,
                        onError: { error in
                         rxFatalErrorInDebug("Binding error: \(error)")
diff --git a/RxCocoa/Common/RxTarget.swift b/RxCocoa/Common/RxTarget.swift
index 5a2c464b0..4a4efcb15 100644
--- a/RxCocoa/Common/RxTarget.swift
+++ b/RxCocoa/Common/RxTarget.swift
@@ -11,7 +11,8 @@ import Foundation
 import RxSwift
 
 class RxTarget : NSObject
-               , Disposable {
+               , Disposable
+               , @unchecked Sendable {
     
     private var retainSelf: RxTarget?
     
diff --git a/RxCocoa/Foundation/NSObject+Rx+KVORepresentable.swift b/RxCocoa/Foundation/NSObject+Rx+KVORepresentable.swift
index 1be5a212d..96fe0862f 100644
--- a/RxCocoa/Foundation/NSObject+Rx+KVORepresentable.swift
+++ b/RxCocoa/Foundation/NSObject+Rx+KVORepresentable.swift
@@ -38,7 +38,7 @@ extension Reactive where Base: NSObject {
      */
     public func observe<Element: KVORepresentable>(_ type: Element.Type, _ keyPath: String, options: KeyValueObservingOptions = [.new, .initial], retainSelf: Bool = true) -> Observable<Element?> {
         return self.observe(Element.KVOType.self, keyPath, options: options, retainSelf: retainSelf)
-            .map(Element.init)
+            .map({ Element(KVOValue: $0) })
     }
 }
 
@@ -52,7 +52,7 @@ extension Reactive where Base: NSObject {
         */
         public func observeWeakly<Element: KVORepresentable>(_ type: Element.Type, _ keyPath: String, options: KeyValueObservingOptions = [.new, .initial]) -> Observable<Element?> {
             return self.observeWeakly(Element.KVOType.self, keyPath, options: options)
-                .map(Element.init)
+                .map({ Element(KVOValue: $0) })
         }
     }
 #endif
diff --git a/RxCocoa/Foundation/NSObject+Rx+RawRepresentable.swift b/RxCocoa/Foundation/NSObject+Rx+RawRepresentable.swift
index 6e47cb243..40dc9c31b 100644
--- a/RxCocoa/Foundation/NSObject+Rx+RawRepresentable.swift
+++ b/RxCocoa/Foundation/NSObject+Rx+RawRepresentable.swift
@@ -24,7 +24,7 @@ extension Reactive where Base: NSObject {
      */
     public func observe<Element: RawRepresentable>(_ type: Element.Type, _ keyPath: String, options: KeyValueObservingOptions = [.new, .initial], retainSelf: Bool = true) -> Observable<Element?> where Element.RawValue: KVORepresentable {
         return self.observe(Element.RawValue.KVOType.self, keyPath, options: options, retainSelf: retainSelf)
-            .map(Element.init)
+            .map({ Element(KVOValue: $0) })
     }
 }
 
@@ -44,7 +44,7 @@ extension Reactive where Base: NSObject {
          */
         public func observeWeakly<Element: RawRepresentable>(_ type: Element.Type, _ keyPath: String, options: KeyValueObservingOptions = [.new, .initial]) -> Observable<Element?> where Element.RawValue: KVORepresentable {
             return self.observeWeakly(Element.RawValue.KVOType.self, keyPath, options: options)
-                .map(Element.init)
+                .map({ Element(KVOValue: $0) })
         }
     }
 #endif
diff --git a/RxCocoa/Foundation/NSObject+Rx.swift b/RxCocoa/Foundation/NSObject+Rx.swift
index 2f1572416..2e16f0a07 100644
--- a/RxCocoa/Foundation/NSObject+Rx.swift
+++ b/RxCocoa/Foundation/NSObject+Rx.swift
@@ -360,7 +360,8 @@ private protocol KVOObservableProtocol {
 
 private final class KVOObserver
     : _RXKVOObserver
-    , Disposable {
+    , Disposable
+    , @unchecked Sendable {
     typealias Callback = (Any?) -> Void
 
     var retainSelf: KVOObserver?
@@ -373,7 +374,8 @@ private final class KVOObserver
         super.init(target: parent.target, retainTarget: parent.retainTarget, keyPath: parent.keyPath, options: parent.options.nsOptions, callback: callback)
         self.retainSelf = self
     }
-
+    
+    @Sendable
     override func dispose() {
         super.dispose()
         self.retainSelf = nil
@@ -388,7 +390,8 @@ private final class KVOObserver
 
 private final class KVOObservable<Element>
     : ObservableType
-    , KVOObservableProtocol {
+    , KVOObservableProtocol
+    , @unchecked Sendable {
     typealias Element = Element?
 
     unowned var target: AnyObject
@@ -483,7 +486,7 @@ private extension KeyValueObservingOptions {
         options: KeyValueObservingOptions
         ) -> Observable<AnyObject?> {
 
-        weak var weakTarget: AnyObject? = target
+        nonisolated(unsafe) weak var weakTarget: AnyObject? = target
 
         let propertyName = keyPathSections[0]
         let remainingPaths = Array(keyPathSections[1..<keyPathSections.count])
diff --git a/RxCocoa/Foundation/URLSession+Rx.swift b/RxCocoa/Foundation/URLSession+Rx.swift
index 93e65ccf8..26ac59cce 100644
--- a/RxCocoa/Foundation/URLSession+Rx.swift
+++ b/RxCocoa/Foundation/URLSession+Rx.swift
@@ -149,7 +149,7 @@ extension Reactive where Base: URLSession {
 
             task.resume()
 
-            return Disposables.create(with: task.cancel)
+            return Disposables.create(with: { task.cancel() })
         }
     }
 
diff --git a/RxCocoa/Traits/Driver/Driver+Subscription.swift b/RxCocoa/Traits/Driver/Driver+Subscription.swift
index 0b9024c75..0a3f6cf2c 100644
--- a/RxCocoa/Traits/Driver/Driver+Subscription.swift
+++ b/RxCocoa/Traits/Driver/Driver+Subscription.swift
@@ -157,12 +157,12 @@ extension SharedSequenceConvertibleType where SharingStrategy == DriverSharingSt
     */
     public func drive<Object: AnyObject>(
         with object: Object,
-        onNext: ((Object, Element) -> Void)? = nil,
-        onCompleted: ((Object) -> Void)? = nil,
-        onDisposed: ((Object) -> Void)? = nil
+        onNext: (@Sendable @MainActor (Object, Element) -> Void)? = nil,
+        onCompleted: (@Sendable @MainActor (Object) -> Void)? = nil,
+        onDisposed: (@Sendable (Object) -> Void)? = nil
     ) -> Disposable {
         MainScheduler.ensureRunningOnMainThread(errorMessage: errorMessage)
-        return self.asObservable().subscribe(with: object, onNext: onNext, onCompleted: onCompleted, onDisposed: onDisposed)
+        return self.asObservable().subscribe(with: object, onNext: onNext.flatMap({ MainScheduler.assumeMainActor($0) }), onCompleted: onCompleted.flatMap({ MainScheduler.assumeMainActor($0) }), onDisposed: onDisposed)
     }
     
     /**
@@ -179,12 +179,12 @@ extension SharedSequenceConvertibleType where SharingStrategy == DriverSharingSt
     - returns: Subscription object used to unsubscribe from the observable sequence.
     */
     public func drive(
-        onNext: ((Element) -> Void)? = nil,
-        onCompleted: (() -> Void)? = nil,
-        onDisposed: (() -> Void)? = nil
+        onNext: (@Sendable @MainActor (Element) -> Void)? = nil,
+        onCompleted: (@Sendable @MainActor () -> Void)? = nil,
+        onDisposed: (@Sendable () -> Void)? = nil
     ) -> Disposable {
         MainScheduler.ensureRunningOnMainThread(errorMessage: errorMessage)
-        return self.asObservable().subscribe(onNext: onNext, onCompleted: onCompleted, onDisposed: onDisposed)
+        return self.asObservable().subscribe(onNext: onNext.flatMap({ MainScheduler.assumeMainActor($0) }), onCompleted: onCompleted.flatMap({ MainScheduler.assumeMainActor($0) }), onDisposed: onDisposed)
     }
 
     /**
diff --git a/RxCocoa/Traits/Driver/ObservableConvertibleType+Driver.swift b/RxCocoa/Traits/Driver/ObservableConvertibleType+Driver.swift
index bcac66b66..16e79abb2 100644
--- a/RxCocoa/Traits/Driver/ObservableConvertibleType+Driver.swift
+++ b/RxCocoa/Traits/Driver/ObservableConvertibleType+Driver.swift
@@ -45,12 +45,12 @@ extension ObservableConvertibleType {
     - parameter onErrorRecover: Calculates driver that continues to drive the sequence in case of error.
     - returns: Driver trait.
     */
-    public func asDriver(onErrorRecover: @escaping (_ error: Swift.Error) -> Driver<Element>) -> Driver<Element> {
+    public func asDriver(onErrorRecover: @escaping @Sendable @MainActor (_ error: Swift.Error) -> Driver<Element>) -> Driver<Element> {
         let source = self
             .asObservable()
             .observe(on:DriverSharingStrategy.scheduler)
             .catch { error in
-                onErrorRecover(error).asObservable()
+                MainScheduler.assumeMainActor(onErrorRecover)(error).asObservable()
             }
         return Driver(source)
     }
diff --git a/RxCocoa/Traits/SharedSequence/ObservableConvertibleType+SharedSequence.swift b/RxCocoa/Traits/SharedSequence/ObservableConvertibleType+SharedSequence.swift
index 20ddf868f..5f6f6ada1 100644
--- a/RxCocoa/Traits/SharedSequence/ObservableConvertibleType+SharedSequence.swift
+++ b/RxCocoa/Traits/SharedSequence/ObservableConvertibleType+SharedSequence.swift
@@ -45,7 +45,7 @@ extension ObservableConvertibleType {
      - parameter onErrorRecover: Calculates driver that continues to drive the sequence in case of error.
      - returns: Driving observable sequence.
      */
-    public func asSharedSequence<S>(sharingStrategy: S.Type = S.self, onErrorRecover: @escaping (_ error: Swift.Error) -> SharedSequence<S, Element>) -> SharedSequence<S, Element> {
+    public func asSharedSequence<S>(sharingStrategy: S.Type = S.self, onErrorRecover: @escaping @Sendable (_ error: Swift.Error) -> SharedSequence<S, Element>) -> SharedSequence<S, Element> {
         let source = self
             .asObservable()
             .observe(on:S.scheduler)
diff --git a/RxCocoa/Traits/SharedSequence/SchedulerType+SharedSequence.swift b/RxCocoa/Traits/SharedSequence/SchedulerType+SharedSequence.swift
index 5111e06d8..d4d63016f 100644
--- a/RxCocoa/Traits/SharedSequence/SchedulerType+SharedSequence.swift
+++ b/RxCocoa/Traits/SharedSequence/SchedulerType+SharedSequence.swift
@@ -28,7 +28,7 @@ public enum SharingScheduler {
 
      **This shouldn't be used in normal release builds.**
      */
-    static public func mock(makeScheduler: @escaping () -> SchedulerType, action: () throws -> Void) rethrows {
+    static public func mock(makeScheduler: @escaping @Sendable () -> SchedulerType, action: () throws -> Void) rethrows {
         let originalMake = make
         make = makeScheduler
         defer {
diff --git a/RxCocoa/Traits/SharedSequence/SharedSequence+Operators+arity.swift b/RxCocoa/Traits/SharedSequence/SharedSequence+Operators+arity.swift
index 4cc967cfb..df6b5e478 100644
--- a/RxCocoa/Traits/SharedSequence/SharedSequence+Operators+arity.swift
+++ b/RxCocoa/Traits/SharedSequence/SharedSequence+Operators+arity.swift
@@ -21,7 +21,7 @@ extension SharedSequence {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func zip<O1: SharedSequenceConvertibleType, O2: SharedSequenceConvertibleType>
-        (_ source1: O1, _ source2: O2, resultSelector: @escaping (O1.Element, O2.Element) throws -> Element)
+        (_ source1: O1, _ source2: O2, resultSelector: @escaping @Sendable (O1.Element, O2.Element) throws -> Element)
         -> SharedSequence<O1.SharingStrategy, Element> where SharingStrategy == O1.SharingStrategy,
             SharingStrategy == O2.SharingStrategy {
         let source = Observable.zip(
@@ -59,7 +59,7 @@ extension SharedSequence {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func combineLatest<O1: SharedSequenceConvertibleType, O2: SharedSequenceConvertibleType>
-        (_ source1: O1, _ source2: O2, resultSelector: @escaping (O1.Element, O2.Element) throws -> Element)
+        (_ source1: O1, _ source2: O2, resultSelector: @escaping @Sendable (O1.Element, O2.Element) throws -> Element)
         -> SharedSequence<SharingStrategy, Element> where SharingStrategy == O1.SharingStrategy,
             SharingStrategy == O2.SharingStrategy {
         let source = Observable.combineLatest(
@@ -101,7 +101,7 @@ extension SharedSequence {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func zip<O1: SharedSequenceConvertibleType, O2: SharedSequenceConvertibleType, O3: SharedSequenceConvertibleType>
-        (_ source1: O1, _ source2: O2, _ source3: O3, resultSelector: @escaping (O1.Element, O2.Element, O3.Element) throws -> Element)
+        (_ source1: O1, _ source2: O2, _ source3: O3, resultSelector: @escaping @Sendable (O1.Element, O2.Element, O3.Element) throws -> Element)
         -> SharedSequence<O1.SharingStrategy, Element> where SharingStrategy == O1.SharingStrategy,
             SharingStrategy == O2.SharingStrategy,
             SharingStrategy == O3.SharingStrategy {
@@ -141,7 +141,7 @@ extension SharedSequence {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func combineLatest<O1: SharedSequenceConvertibleType, O2: SharedSequenceConvertibleType, O3: SharedSequenceConvertibleType>
-        (_ source1: O1, _ source2: O2, _ source3: O3, resultSelector: @escaping (O1.Element, O2.Element, O3.Element) throws -> Element)
+        (_ source1: O1, _ source2: O2, _ source3: O3, resultSelector: @escaping @Sendable (O1.Element, O2.Element, O3.Element) throws -> Element)
         -> SharedSequence<SharingStrategy, Element> where SharingStrategy == O1.SharingStrategy,
             SharingStrategy == O2.SharingStrategy,
             SharingStrategy == O3.SharingStrategy {
@@ -185,7 +185,7 @@ extension SharedSequence {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func zip<O1: SharedSequenceConvertibleType, O2: SharedSequenceConvertibleType, O3: SharedSequenceConvertibleType, O4: SharedSequenceConvertibleType>
-        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, resultSelector: @escaping (O1.Element, O2.Element, O3.Element, O4.Element) throws -> Element)
+        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, resultSelector: @escaping @Sendable (O1.Element, O2.Element, O3.Element, O4.Element) throws -> Element)
         -> SharedSequence<O1.SharingStrategy, Element> where SharingStrategy == O1.SharingStrategy,
             SharingStrategy == O2.SharingStrategy,
             SharingStrategy == O3.SharingStrategy,
@@ -227,7 +227,7 @@ extension SharedSequence {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func combineLatest<O1: SharedSequenceConvertibleType, O2: SharedSequenceConvertibleType, O3: SharedSequenceConvertibleType, O4: SharedSequenceConvertibleType>
-        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, resultSelector: @escaping (O1.Element, O2.Element, O3.Element, O4.Element) throws -> Element)
+        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, resultSelector: @escaping @Sendable (O1.Element, O2.Element, O3.Element, O4.Element) throws -> Element)
         -> SharedSequence<SharingStrategy, Element> where SharingStrategy == O1.SharingStrategy,
             SharingStrategy == O2.SharingStrategy,
             SharingStrategy == O3.SharingStrategy,
@@ -273,7 +273,7 @@ extension SharedSequence {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func zip<O1: SharedSequenceConvertibleType, O2: SharedSequenceConvertibleType, O3: SharedSequenceConvertibleType, O4: SharedSequenceConvertibleType, O5: SharedSequenceConvertibleType>
-        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, resultSelector: @escaping (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element) throws -> Element)
+        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, resultSelector: @escaping @Sendable (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element) throws -> Element)
         -> SharedSequence<O1.SharingStrategy, Element> where SharingStrategy == O1.SharingStrategy,
             SharingStrategy == O2.SharingStrategy,
             SharingStrategy == O3.SharingStrategy,
@@ -317,7 +317,7 @@ extension SharedSequence {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func combineLatest<O1: SharedSequenceConvertibleType, O2: SharedSequenceConvertibleType, O3: SharedSequenceConvertibleType, O4: SharedSequenceConvertibleType, O5: SharedSequenceConvertibleType>
-        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, resultSelector: @escaping (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element) throws -> Element)
+        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, resultSelector: @escaping @Sendable (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element) throws -> Element)
         -> SharedSequence<SharingStrategy, Element> where SharingStrategy == O1.SharingStrategy,
             SharingStrategy == O2.SharingStrategy,
             SharingStrategy == O3.SharingStrategy,
@@ -365,7 +365,7 @@ extension SharedSequence {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func zip<O1: SharedSequenceConvertibleType, O2: SharedSequenceConvertibleType, O3: SharedSequenceConvertibleType, O4: SharedSequenceConvertibleType, O5: SharedSequenceConvertibleType, O6: SharedSequenceConvertibleType>
-        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, _ source6: O6, resultSelector: @escaping (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element, O6.Element) throws -> Element)
+        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, _ source6: O6, resultSelector: @escaping @Sendable (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element, O6.Element) throws -> Element)
         -> SharedSequence<O1.SharingStrategy, Element> where SharingStrategy == O1.SharingStrategy,
             SharingStrategy == O2.SharingStrategy,
             SharingStrategy == O3.SharingStrategy,
@@ -411,7 +411,7 @@ extension SharedSequence {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func combineLatest<O1: SharedSequenceConvertibleType, O2: SharedSequenceConvertibleType, O3: SharedSequenceConvertibleType, O4: SharedSequenceConvertibleType, O5: SharedSequenceConvertibleType, O6: SharedSequenceConvertibleType>
-        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, _ source6: O6, resultSelector: @escaping (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element, O6.Element) throws -> Element)
+        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, _ source6: O6, resultSelector: @escaping @Sendable (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element, O6.Element) throws -> Element)
         -> SharedSequence<SharingStrategy, Element> where SharingStrategy == O1.SharingStrategy,
             SharingStrategy == O2.SharingStrategy,
             SharingStrategy == O3.SharingStrategy,
@@ -461,7 +461,7 @@ extension SharedSequence {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func zip<O1: SharedSequenceConvertibleType, O2: SharedSequenceConvertibleType, O3: SharedSequenceConvertibleType, O4: SharedSequenceConvertibleType, O5: SharedSequenceConvertibleType, O6: SharedSequenceConvertibleType, O7: SharedSequenceConvertibleType>
-        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, _ source6: O6, _ source7: O7, resultSelector: @escaping (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element, O6.Element, O7.Element) throws -> Element)
+        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, _ source6: O6, _ source7: O7, resultSelector: @escaping @Sendable (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element, O6.Element, O7.Element) throws -> Element)
         -> SharedSequence<O1.SharingStrategy, Element> where SharingStrategy == O1.SharingStrategy,
             SharingStrategy == O2.SharingStrategy,
             SharingStrategy == O3.SharingStrategy,
@@ -509,7 +509,7 @@ extension SharedSequence {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func combineLatest<O1: SharedSequenceConvertibleType, O2: SharedSequenceConvertibleType, O3: SharedSequenceConvertibleType, O4: SharedSequenceConvertibleType, O5: SharedSequenceConvertibleType, O6: SharedSequenceConvertibleType, O7: SharedSequenceConvertibleType>
-        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, _ source6: O6, _ source7: O7, resultSelector: @escaping (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element, O6.Element, O7.Element) throws -> Element)
+        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, _ source6: O6, _ source7: O7, resultSelector: @escaping @Sendable (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element, O6.Element, O7.Element) throws -> Element)
         -> SharedSequence<SharingStrategy, Element> where SharingStrategy == O1.SharingStrategy,
             SharingStrategy == O2.SharingStrategy,
             SharingStrategy == O3.SharingStrategy,
@@ -561,7 +561,7 @@ extension SharedSequence {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func zip<O1: SharedSequenceConvertibleType, O2: SharedSequenceConvertibleType, O3: SharedSequenceConvertibleType, O4: SharedSequenceConvertibleType, O5: SharedSequenceConvertibleType, O6: SharedSequenceConvertibleType, O7: SharedSequenceConvertibleType, O8: SharedSequenceConvertibleType>
-        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, _ source6: O6, _ source7: O7, _ source8: O8, resultSelector: @escaping (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element, O6.Element, O7.Element, O8.Element) throws -> Element)
+        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, _ source6: O6, _ source7: O7, _ source8: O8, resultSelector: @escaping @Sendable (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element, O6.Element, O7.Element, O8.Element) throws -> Element)
         -> SharedSequence<O1.SharingStrategy, Element> where SharingStrategy == O1.SharingStrategy,
             SharingStrategy == O2.SharingStrategy,
             SharingStrategy == O3.SharingStrategy,
@@ -611,7 +611,7 @@ extension SharedSequence {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func combineLatest<O1: SharedSequenceConvertibleType, O2: SharedSequenceConvertibleType, O3: SharedSequenceConvertibleType, O4: SharedSequenceConvertibleType, O5: SharedSequenceConvertibleType, O6: SharedSequenceConvertibleType, O7: SharedSequenceConvertibleType, O8: SharedSequenceConvertibleType>
-        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, _ source6: O6, _ source7: O7, _ source8: O8, resultSelector: @escaping (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element, O6.Element, O7.Element, O8.Element) throws -> Element)
+        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, _ source6: O6, _ source7: O7, _ source8: O8, resultSelector: @escaping @Sendable (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element, O6.Element, O7.Element, O8.Element) throws -> Element)
         -> SharedSequence<SharingStrategy, Element> where SharingStrategy == O1.SharingStrategy,
             SharingStrategy == O2.SharingStrategy,
             SharingStrategy == O3.SharingStrategy,
diff --git a/RxCocoa/Traits/SharedSequence/SharedSequence+Operators.swift b/RxCocoa/Traits/SharedSequence/SharedSequence+Operators.swift
index 1d53b03d9..e5180e444 100644
--- a/RxCocoa/Traits/SharedSequence/SharedSequence+Operators.swift
+++ b/RxCocoa/Traits/SharedSequence/SharedSequence+Operators.swift
@@ -17,7 +17,7 @@ extension SharedSequenceConvertibleType {
     - parameter selector: A transform function to apply to each source element.
     - returns: An observable sequence whose elements are the result of invoking the transform function on each element of source.
     */
-    public func map<Result>(_ selector: @escaping (Element) -> Result) -> SharedSequence<SharingStrategy, Result> {
+    public func map<Result>(_ selector: @escaping @Sendable (Element) -> Result) -> SharedSequence<SharingStrategy, Result> {
         let source = self
             .asObservable()
             .map(selector)
@@ -35,7 +35,7 @@ extension SharedSequenceConvertibleType {
      - returns: An observable sequence whose elements are the result of filtering the transform function for each element of the source.
      
      */
-    public func compactMap<Result>(_ selector: @escaping (Element) -> Result?) -> SharedSequence<SharingStrategy, Result> {
+    public func compactMap<Result>(_ selector: @escaping @Sendable (Element) -> Result?) -> SharedSequence<SharingStrategy, Result> {
         let source = self
             .asObservable()
             .compactMap(selector)
@@ -51,7 +51,7 @@ extension SharedSequenceConvertibleType {
     - parameter predicate: A function to test each source element for a condition.
     - returns: An observable sequence that contains elements from the input sequence that satisfy the condition.
     */
-    public func filter(_ predicate: @escaping (Element) -> Bool) -> SharedSequence<SharingStrategy, Element> {
+    public func filter(_ predicate: @escaping @Sendable (Element) -> Bool) -> SharedSequence<SharingStrategy, Element> {
         let source = self
             .asObservable()
             .filter(predicate)
@@ -92,7 +92,7 @@ extension SharedSequenceConvertibleType {
      - returns: An observable sequence whose elements are the result of invoking the transform function on each element of source producing an
      Observable of Observable sequences and that at any point in time produces the elements of the most recent inner observable sequence that has been received.
      */
-    public func flatMapLatest<Sharing, Result>(_ selector: @escaping (Element) -> SharedSequence<Sharing, Result>)
+    public func flatMapLatest<Sharing, Result>(_ selector: @escaping @Sendable (Element) -> SharedSequence<Sharing, Result>)
         -> SharedSequence<Sharing, Result> {
         let source: Observable<Result> = self
             .asObservable()
@@ -111,7 +111,7 @@ extension SharedSequenceConvertibleType {
      - parameter selector: A transform function to apply to element that was observed while no observable is executing in parallel.
      - returns: An observable sequence whose elements are the result of invoking the one-to-many transform function on each element of the input sequence that was received while no other sequence was being calculated.
      */
-    public func flatMapFirst<Sharing, Result>(_ selector: @escaping (Element) -> SharedSequence<Sharing, Result>)
+    public func flatMapFirst<Sharing, Result>(_ selector: @escaping @Sendable (Element) -> SharedSequence<Sharing, Result>)
         -> SharedSequence<Sharing, Result> {
         let source: Observable<Result> = self
             .asObservable()
@@ -134,7 +134,7 @@ extension SharedSequenceConvertibleType {
      - parameter onDispose: Action to invoke after subscription to source observable has been disposed for any reason. It can be either because sequence terminates for some reason or observer subscription being disposed.
      - returns: The source sequence with the side-effecting behavior applied.
      */
-    public func `do`(onNext: ((Element) -> Void)? = nil, afterNext: ((Element) -> Void)? = nil, onCompleted: (() -> Void)? = nil, afterCompleted: (() -> Void)? = nil, onSubscribe: (() -> Void)? = nil, onSubscribed: (() -> Void)? = nil, onDispose: (() -> Void)? = nil)
+    public func `do`(onNext: (@Sendable (Element) -> Void)? = nil, afterNext: (@Sendable (Element) -> Void)? = nil, onCompleted: (@Sendable () -> Void)? = nil, afterCompleted: (@Sendable () -> Void)? = nil, onSubscribe: (@Sendable () -> Void)? = nil, onSubscribed: (@Sendable () -> Void)? = nil, onDispose: (@Sendable () -> Void)? = nil)
         -> SharedSequence<SharingStrategy, Element> {
         let source = self.asObservable()
             .do(onNext: onNext, afterNext: afterNext, onCompleted: onCompleted, afterCompleted: afterCompleted, onSubscribe: onSubscribe, onSubscribed: onSubscribed, onDispose: onDispose)
@@ -184,7 +184,7 @@ extension SharedSequenceConvertibleType {
     - parameter keySelector: A function to compute the comparison key for each element.
     - returns: An observable sequence only containing the distinct contiguous elements, based on a computed key value, from the source sequence.
     */
-    public func distinctUntilChanged<Key: Equatable>(_ keySelector: @escaping (Element) -> Key) -> SharedSequence<SharingStrategy, Element> {
+    public func distinctUntilChanged<Key: Equatable>(_ keySelector: @escaping @Sendable (Element) -> Key) -> SharedSequence<SharingStrategy, Element> {
         let source = self.asObservable()
             .distinctUntilChanged(keySelector, comparer: { $0 == $1 })
         return SharedSequence(source)
@@ -196,7 +196,7 @@ extension SharedSequenceConvertibleType {
     - parameter comparer: Equality comparer for computed key values.
     - returns: An observable sequence only containing the distinct contiguous elements, based on `comparer`, from the source sequence.
     */
-    public func distinctUntilChanged(_ comparer: @escaping (Element, Element) -> Bool) -> SharedSequence<SharingStrategy, Element> {
+    public func distinctUntilChanged(_ comparer: @escaping @Sendable (Element, Element) -> Bool) -> SharedSequence<SharingStrategy, Element> {
         let source = self.asObservable()
             .distinctUntilChanged({ $0 }, comparer: comparer)
         return SharedSequence<SharingStrategy, Element>(source)
@@ -209,7 +209,7 @@ extension SharedSequenceConvertibleType {
     - parameter comparer: Equality comparer for computed key values.
     - returns: An observable sequence only containing the distinct contiguous elements, based on a computed key value and the comparer, from the source sequence.
     */
-    public func distinctUntilChanged<K>(_ keySelector: @escaping (Element) -> K, comparer: @escaping (K, K) -> Bool) -> SharedSequence<SharingStrategy, Element> {
+    public func distinctUntilChanged<K>(_ keySelector: @escaping @Sendable (Element) -> K, comparer: @escaping @Sendable (K, K) -> Bool) -> SharedSequence<SharingStrategy, Element> {
         let source = self.asObservable()
             .distinctUntilChanged(keySelector, comparer: comparer)
         return SharedSequence<SharingStrategy, Element>(source)
@@ -226,7 +226,7 @@ extension SharedSequenceConvertibleType {
     - parameter selector: A transform function to apply to each element.
     - returns: An observable sequence whose elements are the result of invoking the one-to-many transform function on each element of the input sequence.
     */
-    public func flatMap<Sharing, Result>(_ selector: @escaping (Element) -> SharedSequence<Sharing, Result>) -> SharedSequence<Sharing, Result> {
+    public func flatMap<Sharing, Result>(_ selector: @escaping @Sendable (Element) -> SharedSequence<Sharing, Result>) -> SharedSequence<Sharing, Result> {
         let source = self.asObservable()
             .flatMap(selector)
         
@@ -355,7 +355,7 @@ extension SharedSequenceConvertibleType {
     - parameter accumulator: An accumulator function to be invoked on each element.
     - returns: An observable sequence containing the accumulated values.
     */
-    public func scan<A>(_ seed: A, accumulator: @escaping (A, Element) -> A)
+    public func scan<A>(_ seed: A, accumulator: @escaping @Sendable (A, Element) -> A)
         -> SharedSequence<SharingStrategy, A> {
         let source = self.asObservable()
             .scan(seed, accumulator: accumulator)
@@ -398,7 +398,7 @@ extension SharedSequence {
      - parameter resultSelector: Function to invoke for each series of elements at corresponding indexes in the sources.
      - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
      */
-    public static func zip<Collection: Swift.Collection, Result>(_ collection: Collection, resultSelector: @escaping ([Element]) throws -> Result) -> SharedSequence<SharingStrategy, Result>
+    public static func zip<Collection: Swift.Collection, Result>(_ collection: Collection, resultSelector: @escaping @Sendable ([Element]) throws -> Result) -> SharedSequence<SharingStrategy, Result>
         where Collection.Element == SharedSequence<SharingStrategy, Element> {
         let source = Observable.zip(collection.map { $0.asSharedSequence().asObservable() }, resultSelector: resultSelector)
         return SharedSequence<SharingStrategy, Result>(source)
@@ -425,7 +425,7 @@ extension SharedSequence {
      - parameter resultSelector: Function to invoke whenever any of the sources produces an element.
      - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
      */
-    public static func combineLatest<Collection: Swift.Collection, Result>(_ collection: Collection, resultSelector: @escaping ([Element]) throws -> Result) -> SharedSequence<SharingStrategy, Result>
+    public static func combineLatest<Collection: Swift.Collection, Result>(_ collection: Collection, resultSelector: @escaping @Sendable ([Element]) throws -> Result) -> SharedSequence<SharingStrategy, Result>
         where Collection.Element == SharedSequence<SharingStrategy, Element> {
         let source = Observable.combineLatest(collection.map { $0.asObservable() }, resultSelector: resultSelector)
         return SharedSequence<SharingStrategy, Result>(source)
@@ -458,7 +458,7 @@ extension SharedSequenceConvertibleType where SharingStrategy == SignalSharingSt
      */
     public func withUnretained<Object: AnyObject, Out>(
         _ obj: Object,
-        resultSelector: @escaping (Object, Element) -> Out
+        resultSelector: @escaping @Sendable (Object, Element) -> Out
     ) -> SharedSequence<SharingStrategy, Out> {
         SharedSequence(self.asObservable().withUnretained(obj, resultSelector: resultSelector))
     }
@@ -482,7 +482,7 @@ extension SharedSequenceConvertibleType where SharingStrategy == DriverSharingSt
     @available(*, message: "withUnretained has been deprecated for Driver. Consider using `drive(with:onNext:onCompleted:onDisposed:)`, instead", unavailable)
     public func withUnretained<Object: AnyObject, Out>(
         _ obj: Object,
-        resultSelector: @escaping (Object, Element) -> Out
+        resultSelector: @escaping @Sendable (Object, Element) -> Out
     ) -> SharedSequence<SharingStrategy, Out> {
         SharedSequence(self.asObservable().withUnretained(obj, resultSelector: resultSelector))
     }
@@ -503,7 +503,7 @@ extension SharedSequenceConvertibleType {
     - parameter resultSelector: Function to invoke for each element from the self combined with the latest element from the second source, if any.
     - returns: An observable sequence containing the result of combining each element of the self  with the latest element from the second source, if any, using the specified result selector function.
     */
-    public func withLatestFrom<SecondO: SharedSequenceConvertibleType, ResultType>(_ second: SecondO, resultSelector: @escaping (Element, SecondO.Element) -> ResultType) -> SharedSequence<SharingStrategy, ResultType> where SecondO.SharingStrategy == SharingStrategy {
+    public func withLatestFrom<SecondO: SharedSequenceConvertibleType, ResultType>(_ second: SecondO, resultSelector: @escaping @Sendable (Element, SecondO.Element) -> ResultType) -> SharedSequence<SharingStrategy, ResultType> where SecondO.SharingStrategy == SharingStrategy {
         let source = self.asObservable()
             .withLatestFrom(second.asSharedSequence(), resultSelector: resultSelector)
 
diff --git a/RxCocoa/Traits/SharedSequence/SharedSequence.swift b/RxCocoa/Traits/SharedSequence/SharedSequence.swift
index 4596c8ec0..328d9085e 100644
--- a/RxCocoa/Traits/SharedSequence/SharedSequence.swift
+++ b/RxCocoa/Traits/SharedSequence/SharedSequence.swift
@@ -136,7 +136,7 @@ extension SharedSequence {
      - parameter observableFactory: Observable factory function to invoke for each observer that subscribes to the resulting sequence.
      - returns: An observable sequence whose observers trigger an invocation of the given observable factory function.
      */
-    public static func deferred(_ observableFactory: @escaping () -> SharedSequence<SharingStrategy, Element>)
+    public static func deferred(_ observableFactory: @escaping @Sendable () -> SharedSequence<SharingStrategy, Element>)
         -> SharedSequence<SharingStrategy, Element> {
         SharedSequence(Observable.deferred { observableFactory().asObservable() })
     }
diff --git a/RxCocoa/Traits/Signal/ObservableConvertibleType+Signal.swift b/RxCocoa/Traits/Signal/ObservableConvertibleType+Signal.swift
index b962d4ed0..94b5c7d4e 100644
--- a/RxCocoa/Traits/Signal/ObservableConvertibleType+Signal.swift
+++ b/RxCocoa/Traits/Signal/ObservableConvertibleType+Signal.swift
@@ -45,12 +45,12 @@ extension ObservableConvertibleType {
      - parameter onErrorRecover: Calculates signal that continues to emit the sequence in case of error.
      - returns: Signal trait.
      */
-    public func asSignal(onErrorRecover: @escaping (_ error: Swift.Error) -> Signal<Element>) -> Signal<Element> {
+    public func asSignal(onErrorRecover: @escaping @Sendable @MainActor (_ error: Swift.Error) -> Signal<Element>) -> Signal<Element> {
         let source = self
             .asObservable()
             .observe(on: SignalSharingStrategy.scheduler)
             .catch { error in
-                onErrorRecover(error).asObservable()
+                MainScheduler.assumeMainActor(onErrorRecover)(error).asObservable()
             }
         return Signal(source)
     }
diff --git a/RxCocoa/Traits/Signal/Signal+Subscription.swift b/RxCocoa/Traits/Signal/Signal+Subscription.swift
index 4a6add336..2e0d52f01 100644
--- a/RxCocoa/Traits/Signal/Signal+Subscription.swift
+++ b/RxCocoa/Traits/Signal/Signal+Subscription.swift
@@ -132,14 +132,14 @@ extension SharedSequenceConvertibleType where SharingStrategy == SignalSharingSt
      */
     public func emit<Object: AnyObject>(
         with object: Object,
-        onNext: ((Object, Element) -> Void)? = nil,
-        onCompleted: ((Object) -> Void)? = nil,
-        onDisposed: ((Object) -> Void)? = nil
+        onNext: (@Sendable @MainActor (Object, Element) -> Void)? = nil,
+        onCompleted: (@Sendable @MainActor (Object) -> Void)? = nil,
+        onDisposed: (@Sendable (Object) -> Void)? = nil
     ) -> Disposable {
         self.asObservable().subscribe(
             with: object,
-            onNext: onNext,
-            onCompleted: onCompleted,
+            onNext: onNext.flatMap({ MainScheduler.assumeMainActor($0) }),
+            onCompleted: onCompleted.flatMap({ MainScheduler.assumeMainActor($0) }),
             onDisposed: onDisposed
         )
     }
@@ -157,11 +157,15 @@ extension SharedSequenceConvertibleType where SharingStrategy == SignalSharingSt
      - returns: Subscription object used to unsubscribe from the observable sequence.
      */
     public func emit(
-        onNext: ((Element) -> Void)? = nil,
-        onCompleted: (() -> Void)? = nil,
-        onDisposed: (() -> Void)? = nil
+        onNext: (@Sendable @MainActor (Element) -> Void)? = nil,
+        onCompleted: (@Sendable @MainActor () -> Void)? = nil,
+        onDisposed: (@Sendable () -> Void)? = nil
     ) -> Disposable {
-        self.asObservable().subscribe(onNext: onNext, onCompleted: onCompleted, onDisposed: onDisposed)
+        self.asObservable().subscribe(
+            onNext: onNext.flatMap({ MainScheduler.assumeMainActor($0) }),
+            onCompleted: onCompleted.flatMap({ MainScheduler.assumeMainActor($0) }),
+            onDisposed: onDisposed
+        )
     }
 
     /**
diff --git a/RxCocoa/iOS/DataSources/RxCollectionViewReactiveArrayDataSource.swift b/RxCocoa/iOS/DataSources/RxCollectionViewReactiveArrayDataSource.swift
index a5fcfd1b1..89c30690b 100644
--- a/RxCocoa/iOS/DataSources/RxCollectionViewReactiveArrayDataSource.swift
+++ b/RxCocoa/iOS/DataSources/RxCollectionViewReactiveArrayDataSource.swift
@@ -50,7 +50,9 @@ class RxCollectionViewReactiveArrayDataSourceSequenceWrapper<Sequence: Swift.Seq
     func collectionView(_ collectionView: UICollectionView, observedEvent: Event<Sequence>) {
         Binder(self) { collectionViewDataSource, sectionModels in
             let sections = Array(sectionModels)
-            collectionViewDataSource.collectionView(collectionView, observedElements: sections)
+            MainScheduler.assumeMainActor(execute: {
+                collectionViewDataSource.collectionView(collectionView, observedElements: sections)
+            })
         }.on(observedEvent)
     }
 }
@@ -61,7 +63,7 @@ class RxCollectionViewReactiveArrayDataSource<Element>
     : _RxCollectionViewReactiveArrayDataSource
     , SectionedViewDataSourceType {
     
-    typealias CellFactory = (UICollectionView, Int, Element) -> UICollectionViewCell
+    typealias CellFactory = @MainActor (UICollectionView, Int, Element) -> UICollectionViewCell
     
     var itemModels: [Element]?
     
diff --git a/RxCocoa/iOS/DataSources/RxPickerViewAdapter.swift b/RxCocoa/iOS/DataSources/RxPickerViewAdapter.swift
index 9142e96da..67b7afa65 100644
--- a/RxCocoa/iOS/DataSources/RxPickerViewAdapter.swift
+++ b/RxCocoa/iOS/DataSources/RxPickerViewAdapter.swift
@@ -12,7 +12,7 @@ import UIKit
 import RxSwift
 
 class RxPickerViewArrayDataSource<T>: NSObject, UIPickerViewDataSource, SectionedViewDataSourceType {
-    fileprivate var items: [T] = []
+    nonisolated(unsafe) fileprivate var items: [T] = []
     
     func model(at indexPath: IndexPath) throws -> Any {
         guard items.indices ~= indexPath.row else {
@@ -38,7 +38,9 @@ class RxPickerViewSequenceDataSource<Sequence: Swift.Sequence>
     func pickerView(_ pickerView: UIPickerView, observedEvent: Event<Sequence>) {
         Binder(self) { dataSource, items in
             dataSource.items = items
-            pickerView.reloadAllComponents()
+            MainScheduler.assumeMainActor(execute: {
+                pickerView.reloadAllComponents()
+            })
         }
         .on(observedEvent.map(Array.init))
     }
@@ -48,7 +50,7 @@ final class RxStringPickerViewAdapter<Sequence: Swift.Sequence>
     : RxPickerViewSequenceDataSource<Sequence>
     , UIPickerViewDelegate {
     
-    typealias TitleForRow = (Int, Sequence.Element) -> String?
+    typealias TitleForRow = @MainActor (Int, Sequence.Element) -> String?
     private let titleForRow: TitleForRow
     
     init(titleForRow: @escaping TitleForRow) {
@@ -62,7 +64,7 @@ final class RxStringPickerViewAdapter<Sequence: Swift.Sequence>
 }
 
 final class RxAttributedStringPickerViewAdapter<Sequence: Swift.Sequence>: RxPickerViewSequenceDataSource<Sequence>, UIPickerViewDelegate {
-    typealias AttributedTitleForRow = (Int, Sequence.Element) -> NSAttributedString?
+    typealias AttributedTitleForRow = @MainActor (Int, Sequence.Element) -> NSAttributedString?
     private let attributedTitleForRow: AttributedTitleForRow
     
     init(attributedTitleForRow: @escaping AttributedTitleForRow) {
@@ -76,7 +78,7 @@ final class RxAttributedStringPickerViewAdapter<Sequence: Swift.Sequence>: RxPic
 }
 
 final class RxPickerViewAdapter<Sequence: Swift.Sequence>: RxPickerViewSequenceDataSource<Sequence>, UIPickerViewDelegate {
-    typealias ViewForRow = (Int, Sequence.Element, UIView?) -> UIView
+    typealias ViewForRow = @MainActor (Int, Sequence.Element, UIView?) -> UIView
     private let viewForRow: ViewForRow
     
     init(viewForRow: @escaping ViewForRow) {
diff --git a/RxCocoa/iOS/DataSources/RxTableViewReactiveArrayDataSource.swift b/RxCocoa/iOS/DataSources/RxTableViewReactiveArrayDataSource.swift
index f77eec8f8..8699dfc32 100644
--- a/RxCocoa/iOS/DataSources/RxTableViewReactiveArrayDataSource.swift
+++ b/RxCocoa/iOS/DataSources/RxTableViewReactiveArrayDataSource.swift
@@ -50,7 +50,9 @@ class RxTableViewReactiveArrayDataSourceSequenceWrapper<Sequence: Swift.Sequence
     func tableView(_ tableView: UITableView, observedEvent: Event<Sequence>) {
         Binder(self) { tableViewDataSource, sectionModels in
             let sections = Array(sectionModels)
-            tableViewDataSource.tableView(tableView, observedElements: sections)
+            MainScheduler.assumeMainActor(execute: {
+                tableViewDataSource.tableView(tableView, observedElements: sections)
+            })
         }.on(observedEvent)
     }
 }
@@ -59,7 +61,7 @@ class RxTableViewReactiveArrayDataSourceSequenceWrapper<Sequence: Swift.Sequence
 class RxTableViewReactiveArrayDataSource<Element>
     : _RxTableViewReactiveArrayDataSource
     , SectionedViewDataSourceType {
-    typealias CellFactory = (UITableView, Int, Element) -> UITableViewCell
+    typealias CellFactory = @MainActor (UITableView, Int, Element) -> UITableViewCell
     
     var itemModels: [Element]?
     
diff --git a/RxCocoa/iOS/Proxies/RxCollectionViewDelegateProxy.swift b/RxCocoa/iOS/Proxies/RxCollectionViewDelegateProxy.swift
index 687e3b61b..c4967a9d0 100644
--- a/RxCocoa/iOS/Proxies/RxCollectionViewDelegateProxy.swift
+++ b/RxCocoa/iOS/Proxies/RxCollectionViewDelegateProxy.swift
@@ -21,6 +21,7 @@ open class RxCollectionViewDelegateProxy
     /// Initializes `RxCollectionViewDelegateProxy`
     ///
     /// - parameter collectionView: Parent object for delegate proxy.
+    nonisolated
     public init(collectionView: UICollectionView) {
         self.collectionView = collectionView
         super.init(scrollView: collectionView)
diff --git a/RxCocoa/iOS/Proxies/RxTableViewDelegateProxy.swift b/RxCocoa/iOS/Proxies/RxTableViewDelegateProxy.swift
index 51094e4cf..d7e42b412 100644
--- a/RxCocoa/iOS/Proxies/RxTableViewDelegateProxy.swift
+++ b/RxCocoa/iOS/Proxies/RxTableViewDelegateProxy.swift
@@ -19,6 +19,7 @@ open class RxTableViewDelegateProxy
     public weak private(set) var tableView: UITableView?
 
     /// - parameter tableView: Parent object for delegate proxy.
+    nonisolated
     public init(tableView: UITableView) {
         self.tableView = tableView
         super.init(scrollView: tableView)
diff --git a/RxCocoa/iOS/Proxies/RxTextViewDelegateProxy.swift b/RxCocoa/iOS/Proxies/RxTextViewDelegateProxy.swift
index 22b574ce1..8f3f4484a 100644
--- a/RxCocoa/iOS/Proxies/RxTextViewDelegateProxy.swift
+++ b/RxCocoa/iOS/Proxies/RxTextViewDelegateProxy.swift
@@ -19,6 +19,7 @@ open class RxTextViewDelegateProxy
     public weak private(set) var textView: UITextView?
 
     /// - parameter textview: Parent object for delegate proxy.
+    nonisolated
     public init(textView: UITextView) {
         self.textView = textView
         super.init(scrollView: textView)
diff --git a/RxCocoa/iOS/UIActivityIndicatorView+Rx.swift b/RxCocoa/iOS/UIActivityIndicatorView+Rx.swift
index 5f1876b8f..5e049abf7 100644
--- a/RxCocoa/iOS/UIActivityIndicatorView+Rx.swift
+++ b/RxCocoa/iOS/UIActivityIndicatorView+Rx.swift
@@ -14,13 +14,17 @@ import RxSwift
 extension Reactive where Base: UIActivityIndicatorView {
     /// Bindable sink for `startAnimating()`, `stopAnimating()` methods.
     public var isAnimating: Binder<Bool> {
-        Binder(self.base) { activityIndicator, active in
-            if active {
-                activityIndicator.startAnimating()
-            } else {
-                activityIndicator.stopAnimating()
+        MainScheduler.assumeMainActor(execute: {
+            Binder(self.base) { activityIndicator, active in
+                MainScheduler.assumeMainActor(execute: {
+                    if active {
+                        activityIndicator.startAnimating()
+                    } else {
+                        activityIndicator.stopAnimating()
+                    }
+                })
             }
-        }
+        })
     }
 }
 
diff --git a/RxCocoa/iOS/UIApplication+Rx.swift b/RxCocoa/iOS/UIApplication+Rx.swift
index a8a623e77..35e594aaf 100644
--- a/RxCocoa/iOS/UIApplication+Rx.swift
+++ b/RxCocoa/iOS/UIApplication+Rx.swift
@@ -17,7 +17,7 @@ extension Reactive where Base: UIApplication {
   /// Bindable sink for `isNetworkActivityIndicatorVisible`.
   public var isNetworkActivityIndicatorVisible: Binder<Bool> {
     return Binder(self.base) { application, active in
-      application.isNetworkActivityIndicatorVisible = active
+      MainScheduler.assumeMainActor(execute: { application.isNetworkActivityIndicatorVisible = active })
     }
   }
 }
diff --git a/RxCocoa/iOS/UIBarButtonItem+Rx.swift b/RxCocoa/iOS/UIBarButtonItem+Rx.swift
index 1c79390e9..85f0c17c7 100644
--- a/RxCocoa/iOS/UIBarButtonItem+Rx.swift
+++ b/RxCocoa/iOS/UIBarButtonItem+Rx.swift
@@ -22,9 +22,11 @@ extension Reactive where Base: UIBarButtonItem {
                     observer.on(.completed)
                     return Disposables.create()
                 }
-                let target = BarButtonItemTarget(barButtonItem: control) {
-                    observer.on(.next(()))
-                }
+                let target = MainScheduler.assumeMainActor(execute: {
+                    return BarButtonItemTarget(barButtonItem: control) {
+                        observer.on(.next(()))
+                    }
+                })
                 return target
             }
             .take(until: self.deallocated)
@@ -36,14 +38,14 @@ extension Reactive where Base: UIBarButtonItem {
 }
 
 
-@objc
-final class BarButtonItemTarget: RxTarget {
+@objc @MainActor
+final class BarButtonItemTarget: RxTarget, @unchecked Sendable {
     typealias Callback = () -> Void
     
     weak var barButtonItem: UIBarButtonItem?
     var callback: Callback!
     
-    init(barButtonItem: UIBarButtonItem, callback: @escaping () -> Void) {
+    init(barButtonItem: UIBarButtonItem, callback: @escaping @Sendable () -> Void) {
         self.barButtonItem = barButtonItem
         self.callback = callback
         super.init()
@@ -56,11 +58,12 @@ final class BarButtonItemTarget: RxTarget {
 #if DEBUG
         MainScheduler.ensureRunningOnMainThread()
 #endif
-        
-        barButtonItem?.target = nil
-        barButtonItem?.action = nil
-        
-        callback = nil
+        MainScheduler.assumeMainActor(execute: {
+            barButtonItem?.target = nil
+            barButtonItem?.action = nil
+            
+            callback = nil
+        })
     }
     
     @objc func action(_ sender: AnyObject) {
diff --git a/RxCocoa/iOS/UIButton+Rx.swift b/RxCocoa/iOS/UIButton+Rx.swift
index d525ec088..49df2fc2d 100644
--- a/RxCocoa/iOS/UIButton+Rx.swift
+++ b/RxCocoa/iOS/UIButton+Rx.swift
@@ -46,21 +46,27 @@ extension Reactive where Base: UIButton {
     /// Reactive wrapper for `setTitle(_:for:)`
     public func title(for controlState: UIControl.State = []) -> Binder<String?> {
         Binder(self.base) { button, title in
-            button.setTitle(title, for: controlState)
+            MainScheduler.assumeMainActor(execute: {
+                button.setTitle(title, for: controlState)
+            })
         }
     }
 
     /// Reactive wrapper for `setImage(_:for:)`
     public func image(for controlState: UIControl.State = []) -> Binder<UIImage?> {
         Binder(self.base) { button, image in
-            button.setImage(image, for: controlState)
+            MainScheduler.assumeMainActor(execute: {
+                button.setImage(image, for: controlState)
+            })
         }
     }
 
     /// Reactive wrapper for `setBackgroundImage(_:for:)`
     public func backgroundImage(for controlState: UIControl.State = []) -> Binder<UIImage?> {
         Binder(self.base) { button, image in
-            button.setBackgroundImage(image, for: controlState)
+            MainScheduler.assumeMainActor(execute: {
+                button.setBackgroundImage(image, for: controlState)
+            })
         }
     }
     
@@ -75,7 +81,9 @@ extension Reactive where Base: UIButton {
         /// Reactive wrapper for `setAttributedTitle(_:controlState:)`
         public func attributedTitle(for controlState: UIControl.State = []) -> Binder<NSAttributedString?> {
             return Binder(self.base) { button, attributedTitle -> Void in
-                button.setAttributedTitle(attributedTitle, for: controlState)
+                MainScheduler.assumeMainActor(execute: {
+                    button.setAttributedTitle(attributedTitle, for: controlState)
+                })
             }
         }
     }
diff --git a/RxCocoa/iOS/UICollectionView+Rx.swift b/RxCocoa/iOS/UICollectionView+Rx.swift
index 96d69c5bb..748fa14b0 100644
--- a/RxCocoa/iOS/UICollectionView+Rx.swift
+++ b/RxCocoa/iOS/UICollectionView+Rx.swift
@@ -41,7 +41,7 @@ extension Reactive where Base: UICollectionView {
     */
     public func items<Sequence: Swift.Sequence, Source: ObservableType>
         (_ source: Source)
-        -> (_ cellFactory: @escaping (UICollectionView, Int, Sequence.Element) -> UICollectionViewCell)
+        -> (_ cellFactory: @escaping @Sendable (UICollectionView, Int, Sequence.Element) -> UICollectionViewCell)
         -> Disposable where Source.Element == Sequence {
         return { cellFactory in
             let dataSource = RxCollectionViewReactiveArrayDataSourceSequenceWrapper<Sequence>(cellFactory: cellFactory)
@@ -76,7 +76,7 @@ extension Reactive where Base: UICollectionView {
     public func items<Sequence: Swift.Sequence, Cell: UICollectionViewCell, Source: ObservableType>
         (cellIdentifier: String, cellType: Cell.Type = Cell.self)
         -> (_ source: Source)
-        -> (_ configureCell: @escaping (Int, Sequence.Element, Cell) -> Void)
+        -> (_ configureCell: @escaping @Sendable (Int, Sequence.Element, Cell) -> Void)
         -> Disposable where Source.Element == Sequence {
         return { source in
             return { configureCell in
diff --git a/RxCocoa/iOS/UIControl+Rx.swift b/RxCocoa/iOS/UIControl+Rx.swift
index bf4d96882..1ef501edf 100644
--- a/RxCocoa/iOS/UIControl+Rx.swift
+++ b/RxCocoa/iOS/UIControl+Rx.swift
@@ -24,11 +24,13 @@ extension Reactive where Base: UIControl {
                     return Disposables.create()
                 }
 
-                let controlTarget = ControlTarget(control: control, controlEvents: controlEvents) { _ in
-                    observer.on(.next(()))
-                }
-
-                return Disposables.create(with: controlTarget.dispose)
+                return MainScheduler.assumeMainActor(execute: {
+                    let controlTarget = ControlTarget(control: control, controlEvents: controlEvents) { _ in
+                        observer.on(.next(()))
+                    }
+                    
+                    return Disposables.create(with: controlTarget.dispose)
+                })
             }
             .take(until: deallocated)
 
@@ -42,8 +44,8 @@ extension Reactive where Base: UIControl {
     /// - parameter setter: Property value setter.
     public func controlProperty<T>(
         editingEvents: UIControl.Event,
-        getter: @escaping (Base) -> T,
-        setter: @escaping (Base, T) -> Void
+        getter: @escaping @Sendable @MainActor (Base) -> T,
+        setter: @escaping @Sendable @MainActor (Base, T) -> Void
     ) -> ControlProperty<T> {
         let source: Observable<T> = Observable.create { [weak weakControl = base] observer in
                 guard let control = weakControl else {
@@ -51,19 +53,21 @@ extension Reactive where Base: UIControl {
                     return Disposables.create()
                 }
 
-                observer.on(.next(getter(control)))
-
-                let controlTarget = ControlTarget(control: control, controlEvents: editingEvents) { _ in
-                    if let control = weakControl {
-                        observer.on(.next(getter(control)))
-                    }
-                }
+                observer.on(.next(MainScheduler.assumeMainActor(execute: { getter(control) })))
                 
-                return Disposables.create(with: controlTarget.dispose)
+                return MainScheduler.assumeMainActor(execute: {
+                    let controlTarget = ControlTarget(control: control, controlEvents: editingEvents) { [weak weakControl] _ in
+                        if let control = weakControl {
+                            observer.on(.next(MainScheduler.assumeMainActor(execute: { getter(control) })))
+                        }
+                    }
+                    
+                    return Disposables.create(with: controlTarget.dispose)
+                })
             }
             .take(until: deallocated)
 
-        let bindingObserver = Binder(base, binding: setter)
+        let bindingObserver = Binder(base, binding: MainScheduler.assumeMainActor(setter))
 
         return ControlProperty<T>(values: source, valueSink: bindingObserver)
     }
@@ -72,8 +76,8 @@ extension Reactive where Base: UIControl {
     /// an `editingEvent` needs to fire for control property to be updated.
     internal func controlPropertyWithDefaultEvents<T>(
         editingEvents: UIControl.Event = [.allEditingEvents, .valueChanged],
-        getter: @escaping (Base) -> T,
-        setter: @escaping (Base, T) -> Void
+        getter: @escaping @Sendable @MainActor (Base) -> T,
+        setter: @escaping @Sendable @MainActor (Base, T) -> Void
         ) -> ControlProperty<T> {
         return controlProperty(
             editingEvents: editingEvents,
diff --git a/RxCocoa/iOS/UIGestureRecognizer+Rx.swift b/RxCocoa/iOS/UIGestureRecognizer+Rx.swift
index 7dba52024..0926a4ceb 100644
--- a/RxCocoa/iOS/UIGestureRecognizer+Rx.swift
+++ b/RxCocoa/iOS/UIGestureRecognizer+Rx.swift
@@ -12,8 +12,9 @@ import UIKit
 import RxSwift
 
 // This should be only used from `MainScheduler`
-final class GestureTarget<Recognizer: UIGestureRecognizer>: RxTarget {
-    typealias Callback = (Recognizer) -> Void
+@MainActor
+final class GestureTarget<Recognizer: UIGestureRecognizer>: RxTarget, @unchecked Sendable {
+    typealias Callback = @Sendable @MainActor (Recognizer) -> Void
     
     let selector = #selector(GestureTarget.eventHandler(_:))
     
@@ -43,8 +44,10 @@ final class GestureTarget<Recognizer: UIGestureRecognizer>: RxTarget {
     override func dispose() {
         super.dispose()
         
-        self.gestureRecognizer?.removeTarget(self, action: self.selector)
-        self.callback = nil
+        MainScheduler.assumeMainActor(execute: {
+            self.gestureRecognizer?.removeTarget(self, action: self.selector)
+            self.callback = nil
+        })
     }
 }
 
@@ -60,9 +63,11 @@ extension Reactive where Base: UIGestureRecognizer {
                 return Disposables.create()
             }
             
-            let observer = GestureTarget(control) { control in
-                observer.on(.next(control))
-            }
+            let observer = MainScheduler.assumeMainActor(execute: {
+                return GestureTarget(control) { control in
+                    observer.on(.next(control))
+                }
+            })
             
             return observer
         }.take(until: deallocated)
diff --git a/RxCocoa/iOS/UIPickerView+Rx.swift b/RxCocoa/iOS/UIPickerView+Rx.swift
index 92f998cf1..4704ca2cc 100644
--- a/RxCocoa/iOS/UIPickerView+Rx.swift
+++ b/RxCocoa/iOS/UIPickerView+Rx.swift
@@ -69,13 +69,14 @@
                 guard let view = view else {
                     return Observable.empty()
                 }
-
-                let model: [T] = try (0 ..< view.numberOfComponents).map { component in
-                    let row = view.selectedRow(inComponent: component)
-                    return try view.rx.model(at: IndexPath(row: row, section: component))
-                }
-
-                return Observable.just(model)
+                return try MainScheduler.assumeMainActor(execute: {
+                    let model: [T] = try (0 ..< view.numberOfComponents).map { component in
+                        let row = view.selectedRow(inComponent: component)
+                        return try view.rx.model(at: IndexPath(row: row, section: component))
+                    }
+                    
+                    return Observable.just(model)
+                })
             }
             
             return ControlEvent(events: source)
@@ -106,7 +107,7 @@
         
         public func itemTitles<Sequence: Swift.Sequence, Source: ObservableType>
             (_ source: Source)
-            -> (_ titleForRow: @escaping (Int, Sequence.Element) -> String?)
+            -> (_ titleForRow: @escaping @Sendable (Int, Sequence.Element) -> String?)
             -> Disposable where Source.Element == Sequence {
                 return { titleForRow in
                     let adapter = RxStringPickerViewAdapter<Sequence>(titleForRow: titleForRow)
@@ -139,7 +140,7 @@
 
         public func itemAttributedTitles<Sequence: Swift.Sequence, Source: ObservableType>
             (_ source: Source)
-            -> (_ attributedTitleForRow: @escaping (Int, Sequence.Element) -> NSAttributedString?)
+            -> (_ attributedTitleForRow: @escaping @Sendable (Int, Sequence.Element) -> NSAttributedString?)
             -> Disposable where Source.Element == Sequence {
                 return { attributedTitleForRow in
                     let adapter = RxAttributedStringPickerViewAdapter<Sequence>(attributedTitleForRow: attributedTitleForRow)
@@ -178,7 +179,7 @@
 
         public func items<Sequence: Swift.Sequence, Source: ObservableType>
             (_ source: Source)
-            -> (_ viewForRow: @escaping (Int, Sequence.Element, UIView?) -> UIView)
+            -> (_ viewForRow: @escaping @Sendable (Int, Sequence.Element, UIView?) -> UIView)
             -> Disposable where Source.Element == Sequence {
                 return { viewForRow in
                     let adapter = RxPickerViewAdapter<Sequence>(viewForRow: viewForRow)
diff --git a/RxCocoa/iOS/UIRefreshControl+Rx.swift b/RxCocoa/iOS/UIRefreshControl+Rx.swift
index adb484f13..eff23021c 100644
--- a/RxCocoa/iOS/UIRefreshControl+Rx.swift
+++ b/RxCocoa/iOS/UIRefreshControl+Rx.swift
@@ -15,11 +15,13 @@ extension Reactive where Base: UIRefreshControl {
     /// Bindable sink for `beginRefreshing()`, `endRefreshing()` methods.
     public var isRefreshing: Binder<Bool> {
         return Binder(self.base) { refreshControl, refresh in
-            if refresh {
-                refreshControl.beginRefreshing()
-            } else {
-                refreshControl.endRefreshing()
-            }
+            MainScheduler.assumeMainActor(execute: {
+                if refresh {
+                    refreshControl.beginRefreshing()
+                } else {
+                    refreshControl.endRefreshing()
+                }
+            })
         }
     }
 
diff --git a/RxCocoa/iOS/UIScrollView+Rx.swift b/RxCocoa/iOS/UIScrollView+Rx.swift
index dc53c02fd..e7b400299 100644
--- a/RxCocoa/iOS/UIScrollView+Rx.swift
+++ b/RxCocoa/iOS/UIScrollView+Rx.swift
@@ -27,7 +27,9 @@
             let proxy = RxScrollViewDelegateProxy.proxy(for: base)
 
             let bindingObserver = Binder(self.base) { scrollView, contentOffset in
-                scrollView.contentOffset = contentOffset
+                MainScheduler.assumeMainActor(execute: {                
+                    scrollView.contentOffset = contentOffset
+                })
             }
 
             return ControlProperty(values: proxy.contentOffsetBehaviorSubject, valueSink: bindingObserver)
diff --git a/RxCocoa/iOS/UISearchBar+Rx.swift b/RxCocoa/iOS/UISearchBar+Rx.swift
index 1d0229677..6b614e726 100644
--- a/RxCocoa/iOS/UISearchBar+Rx.swift
+++ b/RxCocoa/iOS/UISearchBar+Rx.swift
@@ -28,18 +28,26 @@ extension Reactive where Base: UISearchBar {
     /// Reactive wrapper for `text` property.
     public var value: ControlProperty<String?> {
         let source: Observable<String?> = Observable.deferred { [weak searchBar = self.base as UISearchBar] () -> Observable<String?> in
-            let text = searchBar?.text
-
-            let textDidChange = (searchBar?.rx.delegate.methodInvoked(#selector(UISearchBarDelegate.searchBar(_:textDidChange:))) ?? Observable.empty())
-            let didEndEditing = (searchBar?.rx.delegate.methodInvoked(#selector(UISearchBarDelegate.searchBarTextDidEndEditing(_:))) ?? Observable.empty())
-            
-            return Observable.merge(textDidChange, didEndEditing)
-                    .map { _ in searchBar?.text ?? "" }
+            return MainScheduler.assumeMainActor(execute: {
+                let text = searchBar?.text
+                
+                let textDidChange = (searchBar?.rx.delegate.methodInvoked(#selector(UISearchBarDelegate.searchBar(_:textDidChange:))) ?? Observable.empty())
+                let didEndEditing = (searchBar?.rx.delegate.methodInvoked(#selector(UISearchBarDelegate.searchBarTextDidEndEditing(_:))) ?? Observable.empty())
+                
+                return Observable.merge(textDidChange, didEndEditing)
+                    .map { [weak searchBar] _ in
+                        MainScheduler.assumeMainActor(execute: { [weak searchBar] in
+                            searchBar?.text ?? ""
+                        })
+                    }
                     .startWith(text)
+            })
         }
         
         let bindingObserver = Binder(self.base) { (searchBar, text: String?) in
-            searchBar.text = text
+            MainScheduler.assumeMainActor(execute: {
+                searchBar.text = text
+            })
         }
 
         return ControlProperty(values: source, valueSink: bindingObserver)
@@ -48,7 +56,7 @@ extension Reactive where Base: UISearchBar {
     /// Reactive wrapper for `selectedScopeButtonIndex` property.
     public var selectedScopeButtonIndex: ControlProperty<Int> {
         let source: Observable<Int> = Observable.deferred { [weak source = self.base as UISearchBar] () -> Observable<Int> in
-            let index = source?.selectedScopeButtonIndex ?? 0
+            let index = MainScheduler.assumeMainActor(execute: { source?.selectedScopeButtonIndex ?? 0 })
             
             return (source?.rx.delegate.methodInvoked(#selector(UISearchBarDelegate.searchBar(_:selectedScopeButtonIndexDidChange:))) ?? Observable.empty())
                 .map { a in
@@ -58,7 +66,7 @@ extension Reactive where Base: UISearchBar {
         }
         
         let bindingObserver = Binder(self.base) { (searchBar, index: Int) in
-            searchBar.selectedScopeButtonIndex = index
+            MainScheduler.assumeMainActor(execute: { searchBar.selectedScopeButtonIndex = index })
         }
         
         return ControlProperty(values: source, valueSink: bindingObserver)
diff --git a/RxCocoa/iOS/UISegmentedControl+Rx.swift b/RxCocoa/iOS/UISegmentedControl+Rx.swift
index 613d2e179..d28bbb40c 100644
--- a/RxCocoa/iOS/UISegmentedControl+Rx.swift
+++ b/RxCocoa/iOS/UISegmentedControl+Rx.swift
@@ -31,21 +31,27 @@ extension Reactive where Base: UISegmentedControl {
     /// Reactive wrapper for `setEnabled(_:forSegmentAt:)`
     public func enabledForSegment(at index: Int) -> Binder<Bool> {
         return Binder(self.base) { segmentedControl, segmentEnabled -> Void in
-            segmentedControl.setEnabled(segmentEnabled, forSegmentAt: index)
+            MainScheduler.assumeMainActor(execute: {
+                segmentedControl.setEnabled(segmentEnabled, forSegmentAt: index)
+            })
         }
     }
     
     /// Reactive wrapper for `setTitle(_:forSegmentAt:)`
     public func titleForSegment(at index: Int) -> Binder<String?> {
         return Binder(self.base) { segmentedControl, title -> Void in
-            segmentedControl.setTitle(title, forSegmentAt: index)
+            MainScheduler.assumeMainActor(execute: {
+                segmentedControl.setTitle(title, forSegmentAt: index)
+            })
         }
     }
     
     /// Reactive wrapper for `setImage(_:forSegmentAt:)`
     public func imageForSegment(at index: Int) -> Binder<UIImage?> {
         return Binder(self.base) { segmentedControl, image -> Void in
-            segmentedControl.setImage(image, forSegmentAt: index)
+            MainScheduler.assumeMainActor(execute: {
+                segmentedControl.setImage(image, forSegmentAt: index)
+            })
         }
     }
 
diff --git a/RxCocoa/iOS/UITableView+Rx.swift b/RxCocoa/iOS/UITableView+Rx.swift
index deae7ffe4..7ad6f68bf 100644
--- a/RxCocoa/iOS/UITableView+Rx.swift
+++ b/RxCocoa/iOS/UITableView+Rx.swift
@@ -41,7 +41,7 @@ extension Reactive where Base: UITableView {
      */
     public func items<Sequence: Swift.Sequence, Source: ObservableType>
         (_ source: Source)
-        -> (_ cellFactory: @escaping (UITableView, Int, Sequence.Element) -> UITableViewCell)
+        -> (_ cellFactory: @escaping @Sendable (UITableView, Int, Sequence.Element) -> UITableViewCell)
         -> Disposable
         where Source.Element == Sequence {
             return { cellFactory in
@@ -76,7 +76,7 @@ extension Reactive where Base: UITableView {
     public func items<Sequence: Swift.Sequence, Cell: UITableViewCell, Source: ObservableType>
         (cellIdentifier: String, cellType: Cell.Type = Cell.self)
         -> (_ source: Source)
-        -> (_ configureCell: @escaping (Int, Sequence.Element, Cell) -> Void)
+        -> (_ configureCell: @escaping @Sendable (Int, Sequence.Element, Cell) -> Void)
         -> Disposable
         where Source.Element == Sequence {
         return { source in
diff --git a/RxCocoa/iOS/UITextView+Rx.swift b/RxCocoa/iOS/UITextView+Rx.swift
index 35e219425..c0be60819 100644
--- a/RxCocoa/iOS/UITextView+Rx.swift
+++ b/RxCocoa/iOS/UITextView+Rx.swift
@@ -20,33 +20,39 @@ extension Reactive where Base: UITextView {
     /// Reactive wrapper for `text` property.
     public var value: ControlProperty<String?> {
         let source: Observable<String?> = Observable.deferred { [weak textView = self.base] in
-            let text = textView?.text
-            
-            let textChanged = textView?.textStorage
+            MainScheduler.assumeMainActor(execute: { [weak textView] in
+                let text = textView?.text
+                
+                let textChanged = textView?.textStorage
                 // This project uses text storage notifications because
                 // that's the only way to catch autocorrect changes
                 // in all cases. Other suggestions are welcome.
-                .rx.didProcessEditingRangeChangeInLength
+                    .rx.didProcessEditingRangeChangeInLength
                 // This observe on is here because text storage
                 // will emit event while process is not completely done,
                 // so rebinding a value will cause an exception to be thrown.
-                .observe(on:MainScheduler.asyncInstance)
-                .map { _ in
-                    return textView?.textStorage.string
-                }
+                    .observe(on:MainScheduler.asyncInstance)
+                    .map { [weak textView] _ in
+                        MainScheduler.assumeMainActor(execute: { [weak textView] in
+                            return textView?.textStorage.string
+                        })
+                    }
                 ?? Observable.empty()
-            
-            return textChanged
-                .startWith(text)
+                
+                return textChanged
+                    .startWith(text)
+            })
         }
 
         let bindingObserver = Binder(self.base) { (textView, text: String?) in
             // This check is important because setting text value always clears control state
             // including marked text selection which is important for proper input
             // when IME input method is used.
-            if textView.text != text {
-                textView.text = text
-            }
+            MainScheduler.assumeMainActor(execute: {
+                if textView.text != text {
+                    textView.text = text
+                }
+            })
         }
         
         return ControlProperty(values: source, valueSink: bindingObserver)
@@ -56,33 +62,39 @@ extension Reactive where Base: UITextView {
     /// Reactive wrapper for `attributedText` property.
     public var attributedText: ControlProperty<NSAttributedString?> {
         let source: Observable<NSAttributedString?> = Observable.deferred { [weak textView = self.base] in
-            let attributedText = textView?.attributedText
-            
-            let textChanged: Observable<NSAttributedString?> = textView?.textStorage
+            return MainScheduler.assumeMainActor(execute: {
+                let attributedText = textView?.attributedText
+                
+                let textChanged: Observable<NSAttributedString?> = textView?.textStorage
                 // This project uses text storage notifications because
                 // that's the only way to catch autocorrect changes
                 // in all cases. Other suggestions are welcome.
-                .rx.didProcessEditingRangeChangeInLength
+                    .rx.didProcessEditingRangeChangeInLength
                 // This observe on is here because attributedText storage
                 // will emit event while process is not completely done,
                 // so rebinding a value will cause an exception to be thrown.
-                .observe(on:MainScheduler.asyncInstance)
-                .map { _ in
-                    return textView?.attributedText
-                }
+                    .observe(on:MainScheduler.asyncInstance)
+                    .map { [weak textView] _ in
+                        MainScheduler.assumeMainActor(execute: {
+                            return textView?.attributedText
+                        })
+                    }
                 ?? Observable.empty()
-            
-            return textChanged
-                .startWith(attributedText)
+                
+                return textChanged
+                    .startWith(attributedText)
+            })
         }
         
         let bindingObserver = Binder(self.base) { (textView, attributedText: NSAttributedString?) in
             // This check is important because setting text value always clears control state
             // including marked text selection which is important for proper input
             // when IME input method is used.
-            if textView.attributedText != attributedText {
-                textView.attributedText = attributedText
-            }
+            MainScheduler.assumeMainActor(execute: {
+                if textView.attributedText != attributedText {
+                    textView.attributedText = attributedText
+                }
+            })
         }
         
         return ControlProperty(values: source, valueSink: bindingObserver)
diff --git a/RxCocoa/macOS/NSControl+Rx.swift b/RxCocoa/macOS/NSControl+Rx.swift
index 534f40cab..fe3142a3f 100644
--- a/RxCocoa/macOS/NSControl+Rx.swift
+++ b/RxCocoa/macOS/NSControl+Rx.swift
@@ -47,8 +47,8 @@ extension Reactive where Base: NSControl {
     /// - parameter getter: Property value getter.
     /// - parameter setter: Property value setter.
     public func controlProperty<T>(
-        getter: @escaping (Base) -> T,
-        setter: @escaping (Base, T) -> Void
+        getter: @escaping @Sendable (Base) -> T,
+        setter: @escaping @Sendable (Base, T) -> Void
     ) -> ControlProperty<T> {
         MainScheduler.ensureRunningOnMainThread()
 
diff --git a/RxExample/Extensions/RxCLLocationManagerDelegateProxy.swift b/RxExample/Extensions/RxCLLocationManagerDelegateProxy.swift
index 3efa0940d..9607ea367 100644
--- a/RxExample/Extensions/RxCLLocationManagerDelegateProxy.swift
+++ b/RxExample/Extensions/RxCLLocationManagerDelegateProxy.swift
@@ -10,7 +10,7 @@ import CoreLocation
 import RxSwift
 import RxCocoa
 
-extension CLLocationManager: HasDelegate {
+extension CLLocationManager: @retroactive HasDelegate {
     public typealias Delegate = CLLocationManagerDelegate
 }
 
diff --git a/RxExample/Extensions/RxImagePickerDelegateProxy.swift b/RxExample/Extensions/RxImagePickerDelegateProxy.swift
index ebaab6ff0..5329602c3 100644
--- a/RxExample/Extensions/RxImagePickerDelegateProxy.swift
+++ b/RxExample/Extensions/RxImagePickerDelegateProxy.swift
@@ -15,6 +15,7 @@ import UIKit
 open class RxImagePickerDelegateProxy
     : RxNavigationControllerDelegateProxy, UIImagePickerControllerDelegate {
 
+    nonisolated
     public init(imagePicker: UIImagePickerController) {
         super.init(navigationController: imagePicker)
     }
diff --git a/RxExample/RxDataSources/RxDataSources/TableViewSectionedDataSource.swift b/RxExample/RxDataSources/RxDataSources/TableViewSectionedDataSource.swift
index e92da0bdd..91d0abe9d 100644
--- a/RxExample/RxDataSources/RxDataSources/TableViewSectionedDataSource.swift
+++ b/RxExample/RxDataSources/RxDataSources/TableViewSectionedDataSource.swift
@@ -19,21 +19,21 @@ open class TableViewSectionedDataSource<Section: SectionModelType>
     
     public typealias Item = Section.Item
 
-    public typealias ConfigureCell = (TableViewSectionedDataSource<Section>, UITableView, IndexPath, Item) -> UITableViewCell
-    public typealias TitleForHeaderInSection = (TableViewSectionedDataSource<Section>, Int) -> String?
-    public typealias TitleForFooterInSection = (TableViewSectionedDataSource<Section>, Int) -> String?
-    public typealias CanEditRowAtIndexPath = (TableViewSectionedDataSource<Section>, IndexPath) -> Bool
-    public typealias CanMoveRowAtIndexPath = (TableViewSectionedDataSource<Section>, IndexPath) -> Bool
+    public typealias ConfigureCell = @Sendable @MainActor (TableViewSectionedDataSource<Section>, UITableView, IndexPath, Item) -> UITableViewCell
+    public typealias TitleForHeaderInSection = @Sendable @MainActor (TableViewSectionedDataSource<Section>, Int) -> String?
+    public typealias TitleForFooterInSection = @Sendable @MainActor (TableViewSectionedDataSource<Section>, Int) -> String?
+    public typealias CanEditRowAtIndexPath = @Sendable @MainActor (TableViewSectionedDataSource<Section>, IndexPath) -> Bool
+    public typealias CanMoveRowAtIndexPath = @Sendable @MainActor (TableViewSectionedDataSource<Section>, IndexPath) -> Bool
 
     #if os(iOS)
-        public typealias SectionIndexTitles = (TableViewSectionedDataSource<Section>) -> [String]?
-        public typealias SectionForSectionIndexTitle = (TableViewSectionedDataSource<Section>, _ title: String, _ index: Int) -> Int
+        public typealias SectionIndexTitles = @Sendable @MainActor (TableViewSectionedDataSource<Section>) -> [String]?
+        public typealias SectionForSectionIndexTitle = @Sendable @MainActor (TableViewSectionedDataSource<Section>, _ title: String, _ index: Int) -> Int
     #endif
 
     #if os(iOS)
         public init(
                 configureCell: @escaping ConfigureCell,
-                titleForHeaderInSection: @escaping  TitleForHeaderInSection = { _, _ in nil },
+                titleForHeaderInSection: @escaping TitleForHeaderInSection = { _, _ in nil },
                 titleForFooterInSection: @escaping TitleForFooterInSection = { _, _ in nil },
                 canEditRowAtIndexPath: @escaping CanEditRowAtIndexPath = { _, _ in false },
                 canMoveRowAtIndexPath: @escaping CanMoveRowAtIndexPath = { _, _ in false },
@@ -173,47 +173,49 @@ open class TableViewSectionedDataSource<Section: SectionModelType>
     
 
     // UITableViewDataSource
-    
+    @MainActor
     open func numberOfSections(in tableView: UITableView) -> Int {
         _sectionModels.count
     }
-    
+    @MainActor
     open func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
         guard _sectionModels.count > section else { return 0 }
         return _sectionModels[section].items.count
     }
-    
+    @MainActor
     open func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
         precondition(indexPath.item < _sectionModels[indexPath.section].items.count)
         
         return configureCell(self, tableView, indexPath, self[indexPath])
     }
-    
+    @MainActor
     open func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
         titleForHeaderInSection(self, section)
     }
-   
+    @MainActor
     open func tableView(_ tableView: UITableView, titleForFooterInSection section: Int) -> String? {
         titleForFooterInSection(self, section)
     }
-    
+    @MainActor
     open func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
         canEditRowAtIndexPath(self, indexPath)
     }
-   
+    @MainActor
     open func tableView(_ tableView: UITableView, canMoveRowAt indexPath: IndexPath) -> Bool {
         canMoveRowAtIndexPath(self, indexPath)
     }
-
+    @MainActor
     open func tableView(_ tableView: UITableView, moveRowAt sourceIndexPath: IndexPath, to destinationIndexPath: IndexPath) {
         self._sectionModels.moveFromSourceIndexPath(sourceIndexPath, destinationIndexPath: destinationIndexPath)
     }
 
     #if os(iOS)
+    @MainActor
     open func sectionIndexTitles(for tableView: UITableView) -> [String]? {
         sectionIndexTitles(self)
     }
     
+    @MainActor
     open func tableView(_ tableView: UITableView, sectionForSectionIndexTitle title: String, at index: Int) -> Int {
         sectionForSectionIndexTitle(self, title, index)
     }
diff --git a/RxExample/RxExample-iOSTests/Mocks/MockGitHubAPI.swift b/RxExample/RxExample-iOSTests/Mocks/MockGitHubAPI.swift
index 0bbafc354..69ddf7aa4 100644
--- a/RxExample/RxExample-iOSTests/Mocks/MockGitHubAPI.swift
+++ b/RxExample/RxExample-iOSTests/Mocks/MockGitHubAPI.swift
@@ -9,12 +9,12 @@
 import RxSwift
 
 class MockGitHubAPI : GitHubAPI {
-    let _usernameAvailable: (String) -> Observable<Bool>
-    let _signup: ((String, String)) -> Observable<Bool>
+    let _usernameAvailable: @Sendable (String) -> Observable<Bool>
+    let _signup: @Sendable ((String, String)) -> Observable<Bool>
 
     init(
-        usernameAvailable: @escaping (String) -> Observable<Bool> = notImplemented(),
-        signup: @escaping ((String, String)) -> Observable<Bool> = notImplemented()
+        usernameAvailable: @escaping @Sendable (String) -> Observable<Bool> = notImplemented(),
+        signup: @escaping @Sendable ((String, String)) -> Observable<Bool> = notImplemented()
         ) {
         _usernameAvailable = usernameAvailable
         _signup = signup
diff --git a/RxExample/RxExample-iOSTests/Mocks/MockWireframe.swift b/RxExample/RxExample-iOSTests/Mocks/MockWireframe.swift
index 6696a3c21..089e622df 100644
--- a/RxExample/RxExample-iOSTests/Mocks/MockWireframe.swift
+++ b/RxExample/RxExample-iOSTests/Mocks/MockWireframe.swift
@@ -10,11 +10,11 @@ import RxSwift
 import Foundation
 
 class MockWireframe: Wireframe {
-    let _openURL: (URL) -> Void
-    let _promptFor: (String, Any, [Any]) -> Observable<Any>
+    let _openURL: @Sendable (URL) -> Void
+    let _promptFor: @Sendable (String, Any, [Any]) -> Observable<Any>
 
-    init(openURL: @escaping (URL) -> Void = notImplementedSync(),
-         promptFor: @escaping (String, Any, [Any]) -> Observable<Any> = notImplemented()) {
+    init(openURL: @escaping @Sendable (URL) -> Void = notImplementedSync(),
+         promptFor: @escaping @Sendable (String, Any, [Any]) -> Observable<Any> = notImplemented()) {
         _openURL = openURL
         _promptFor = promptFor
     }
diff --git a/RxExample/RxExample-iOSTests/Mocks/NotImplementedStubs.swift b/RxExample/RxExample-iOSTests/Mocks/NotImplementedStubs.swift
index 7d81e6cc0..557819200 100644
--- a/RxExample/RxExample-iOSTests/Mocks/NotImplementedStubs.swift
+++ b/RxExample/RxExample-iOSTests/Mocks/NotImplementedStubs.swift
@@ -22,25 +22,25 @@ func genericFatal<T>(_ message: String) -> T {
 
 // MARK: Not implemented stubs
 
-func notImplemented<T1, T2>() -> (T1) -> Observable<T2> {
+func notImplemented<T1, T2>() -> @Sendable (T1) -> Observable<T2> {
     return { _ -> Observable<T2> in
         return genericFatal("Not implemented")
     }
 }
 
-func notImplemented<T1, T2, T3>() -> (T1, T2) -> Observable<T3> {
+func notImplemented<T1, T2, T3>() -> @Sendable (T1, T2) -> Observable<T3> {
     return { _, _ -> Observable<T3> in
         return genericFatal("Not implemented")
     }
 }
 
-func notImplemented<T1, T2, T3, T4>() -> (T1, T2, T3) -> Observable<T4> {
+func notImplemented<T1, T2, T3, T4>() -> @Sendable (T1, T2, T3) -> Observable<T4> {
     return { _, _, _ -> Observable<T4> in
         return genericFatal("Not implemented")
     }
 }
 
-func notImplementedSync<T1>() -> (T1) -> Void {
+func notImplementedSync<T1>() -> @Sendable (T1) -> Void {
     return { _ in
         genericFatal("Not implemented")
     }
diff --git a/RxExample/RxExample-iOSTests/TestScheduler+MarbleTests.swift b/RxExample/RxExample-iOSTests/TestScheduler+MarbleTests.swift
index 41a1539a3..3ee35c9cc 100644
--- a/RxExample/RxExample-iOSTests/TestScheduler+MarbleTests.swift
+++ b/RxExample/RxExample-iOSTests/TestScheduler+MarbleTests.swift
@@ -137,10 +137,10 @@ extension TestScheduler {
      - returns: Observable sequence specified by timeline and values.
     */
     func createObservable<T>(_ events: [[Recorded<Event<T>>]]) -> Observable<T> {
-        var attemptCount = 0
+        nonisolated(unsafe) var attemptCount = 0
         print("created for \(events)")
 
-        return Observable.create { observer in
+        return Observable.create { @Sendable observer in
             if attemptCount >= events.count {
                 fatalError("This is attempt # \(attemptCount + 1), but timeline only allows \(events.count).\n\(events)")
             }
@@ -172,7 +172,7 @@ extension TestScheduler {
      - returns: Implementation of method that accepts arguments with parameter `Arg` and returns observable sequence
         with parameter `Ret`.
      */
-    func mock<Arg, Ret>(values: [String: Ret], errors: [String: Swift.Error] = [:], timelineSelector: @escaping (Arg) -> String) -> (Arg) -> Observable<Ret> {
+    func mock<Arg, Ret>(values: [String: Ret], errors: [String: Swift.Error] = [:], timelineSelector: @escaping @Sendable (Arg) -> String) -> (Arg) -> Observable<Ret> {
         return { (parameters: Arg) -> Observable<Ret> in
             let timeline = timelineSelector(parameters)
 
diff --git a/RxExample/RxExample/Examples/GitHubSearchRepositories/GitHubSearchRepositories.swift b/RxExample/RxExample/Examples/GitHubSearchRepositories/GitHubSearchRepositories.swift
index 1f6b1339d..34ecc998f 100644
--- a/RxExample/RxExample/Examples/GitHubSearchRepositories/GitHubSearchRepositories.swift
+++ b/RxExample/RxExample/Examples/GitHubSearchRepositories/GitHubSearchRepositories.swift
@@ -31,7 +31,8 @@ struct GitHubSearchRepositoriesState {
 
 extension GitHubSearchRepositoriesState {
     static let initial = GitHubSearchRepositoriesState(searchText: "")
-
+    
+    @Sendable
     static func reduce(state: GitHubSearchRepositoriesState, command: GitHubCommand) -> GitHubSearchRepositoriesState {
         switch command {
         case .changeSearch(let text):
@@ -73,8 +74,8 @@ struct GithubQuery: Equatable {
  */
 func githubSearchRepositories(
         searchText: Signal<String>,
-        loadNextPageTrigger: @escaping (Driver<GitHubSearchRepositoriesState>) -> Signal<()>,
-        performSearch: @escaping (URL) -> Observable<SearchRepositoriesResponse>
+        loadNextPageTrigger: @escaping @Sendable (Driver<GitHubSearchRepositoriesState>) -> Signal<()>,
+        performSearch: @escaping @Sendable (URL) -> Observable<SearchRepositoriesResponse>
     ) -> Driver<GitHubSearchRepositoriesState> {
 
 
@@ -98,14 +99,14 @@ func githubSearchRepositories(
 
                 return performSearch(nextURL)
                     .asSignal(onErrorJustReturn: .failure(GitHubServiceError.networkError))
-                    .map(GitHubCommand.gitHubResponseReceived)
+                    .map({ GitHubCommand.gitHubResponseReceived($0) })
             }
     )
 
     // this is degenerated feedback loop that doesn't depend on output state
     let inputFeedbackLoop: (Driver<GitHubSearchRepositoriesState>) -> Signal<GitHubCommand> = { state in
         let loadNextPage = loadNextPageTrigger(state).map { _ in GitHubCommand.loadMoreItems }
-        let searchText = searchText.map(GitHubCommand.changeSearch)
+        let searchText = searchText.map({ GitHubCommand.changeSearch(text: $0) })
 
         return Signal.merge(loadNextPage, searchText)
     }
diff --git a/RxExample/RxExample/Examples/ImagePicker/UIImagePickerController+RxCreate.swift b/RxExample/RxExample/Examples/ImagePicker/UIImagePickerController+RxCreate.swift
index 3839bd0a9..1ee5151a2 100644
--- a/RxExample/RxExample/Examples/ImagePicker/UIImagePickerController+RxCreate.swift
+++ b/RxExample/RxExample/Examples/ImagePicker/UIImagePickerController+RxCreate.swift
@@ -25,37 +25,39 @@ func dismissViewController(_ viewController: UIViewController, animated: Bool) {
 }
 
 extension Reactive where Base: UIImagePickerController {
-    static func createWithParent(_ parent: UIViewController?, animated: Bool = true, configureImagePicker: @escaping (UIImagePickerController) throws -> Void = { x in }) -> Observable<UIImagePickerController> {
+    static func createWithParent(_ parent: UIViewController?, animated: Bool = true, configureImagePicker: @escaping @Sendable (UIImagePickerController) throws -> Void = { x in }) -> Observable<UIImagePickerController> {
         return Observable.create { [weak parent] observer in
-            let imagePicker = UIImagePickerController()
-            let dismissDisposable = imagePicker.rx
-                .didCancel
-                .subscribe(onNext: { [weak imagePicker] _ in
-                    guard let imagePicker = imagePicker else {
-                        return
-                    }
-                    dismissViewController(imagePicker, animated: animated)
-                })
-            
-            do {
-                try configureImagePicker(imagePicker)
-            }
-            catch let error {
-                observer.on(.error(error))
-                return Disposables.create()
-            }
-
-            guard let parent = parent else {
-                observer.on(.completed)
-                return Disposables.create()
-            }
-
-            parent.present(imagePicker, animated: animated, completion: nil)
-            observer.on(.next(imagePicker))
-            
-            return Disposables.create(dismissDisposable, Disposables.create {
+            MainScheduler.assumeMainActor(execute: {
+                let imagePicker = UIImagePickerController()
+                let dismissDisposable = imagePicker.rx
+                    .didCancel
+                    .subscribe(onNext: { [weak imagePicker] _ in
+                        guard let imagePicker = imagePicker else {
+                            return
+                        }
+                        dismissViewController(imagePicker, animated: animated)
+                    })
+                
+                do {
+                    try configureImagePicker(imagePicker)
+                }
+                catch let error {
+                    observer.on(.error(error))
+                    return Disposables.create()
+                }
+                
+                guard let parent = parent else {
+                    observer.on(.completed)
+                    return Disposables.create()
+                }
+                
+                parent.present(imagePicker, animated: animated, completion: nil)
+                observer.on(.next(imagePicker))
+                
+                return Disposables.create(dismissDisposable, Disposables.create {
                     dismissViewController(imagePicker, animated: animated)
                 })
+            })
         }
     }
 }
diff --git a/RxExample/RxExample/Feedbacks.swift b/RxExample/RxExample/Feedbacks.swift
index 8dba562a6..b38c2b344 100644
--- a/RxExample/RxExample/Feedbacks.swift
+++ b/RxExample/RxExample/Feedbacks.swift
@@ -6,8 +6,8 @@
 //  Copyright © 2017 Krunoslav Zaher. All rights reserved.
 //
 
-import RxSwift
-import RxCocoa
+@preconcurrency import RxSwift
+@preconcurrency import RxCocoa
 
 // Taken from RxFeedback repo
 
@@ -26,9 +26,9 @@ import RxCocoa
  - returns: Feedback loop performing the effects.
  */
 public func react<State, Query, Event>(
-    query: @escaping (State) -> Query?,
-    areEqual: @escaping (Query, Query) -> Bool,
-    effects: @escaping (Query) -> Observable<Event>
+    query: @escaping @Sendable (State) -> Query?,
+    areEqual: @escaping @Sendable (Query, Query) -> Bool,
+    effects: @escaping @Sendable (Query) -> Observable<Event>
     ) -> (ObservableSchedulerContext<State>) -> Observable<Event> {
     return { state in
         return state.map(query)
@@ -65,8 +65,8 @@ public func react<State, Query, Event>(
  - returns: Feedback loop performing the effects.
  */
 public func react<State, Query: Equatable, Event>(
-    query: @escaping (State) -> Query?,
-    effects: @escaping (Query) -> Observable<Event>
+    query: @escaping @Sendable (State) -> Query?,
+    effects: @escaping @Sendable (Query) -> Observable<Event>
     ) -> (ObservableSchedulerContext<State>) -> Observable<Event> {
     return react(query: query, areEqual: { $0 == $1 }, effects: effects)
 }
@@ -86,9 +86,9 @@ public func react<State, Query: Equatable, Event>(
  - returns: Feedback loop performing the effects.
  */
 public func react<State, Query, Event>(
-    query: @escaping (State) -> Query?,
-    areEqual: @escaping (Query, Query) -> Bool,
-    effects: @escaping (Query) -> Signal<Event>
+    query: @escaping @Sendable (State) -> Query?,
+    areEqual: @escaping @Sendable (Query, Query) -> Bool,
+    effects: @escaping @Sendable (Query) -> Signal<Event>
     ) -> (Driver<State>) -> Signal<Event> {
     return { state in
         let observableSchedulerContext = ObservableSchedulerContext<State>(
@@ -114,8 +114,8 @@ public func react<State, Query, Event>(
  - returns: Feedback loop performing the effects.
  */
 public func react<State, Query: Equatable, Event>(
-    query: @escaping (State) -> Query?,
-    effects: @escaping (Query) -> Signal<Event>
+    query: @escaping @Sendable (State) -> Query?,
+    effects: @escaping @Sendable (Query) -> Signal<Event>
     ) -> (Driver<State>) -> Signal<Event> {
     return { state in
         let observableSchedulerContext = ObservableSchedulerContext<State>(
@@ -141,8 +141,8 @@ public func react<State, Query: Equatable, Event>(
  - returns: Feedback loop performing the effects.
  */
 public func react<State, Query, Event>(
-    query: @escaping (State) -> Query?,
-    effects: @escaping (Query) -> Observable<Event>
+    query: @escaping @Sendable (State) -> Query?,
+    effects: @escaping @Sendable (Query) -> Observable<Event>
     ) -> (ObservableSchedulerContext<State>) -> Observable<Event> {
     return { state in
         return state.map(query)
@@ -172,8 +172,8 @@ public func react<State, Query, Event>(
  - returns: Feedback loop performing the effects.
  */
 public func react<State, Query, Event>(
-    query: @escaping (State) -> Query?,
-    effects: @escaping (Query) -> Signal<Event>
+    query: @escaping @Sendable (State) -> Query?,
+    effects: @escaping @Sendable (Query) -> Signal<Event>
     ) -> (Driver<State>) -> Signal<Event> {
     return { state in
         let observableSchedulerContext = ObservableSchedulerContext<State>(
@@ -200,8 +200,8 @@ public func react<State, Query, Event>(
  - returns: Feedback loop performing the effects.
  */
 public func react<State, Query, Event>(
-    query: @escaping (State) -> Set<Query>,
-    effects: @escaping (Query) -> Observable<Event>
+    query: @escaping @Sendable (State) -> Set<Query>,
+    effects: @escaping @Sendable (Query) -> Observable<Event>
     ) -> (ObservableSchedulerContext<State>) -> Observable<Event> {
     return { state in
         let query = state.map(query)
@@ -250,8 +250,8 @@ extension ObservableType {
  - returns: Feedback loop performing the effects.
  */
 public func react<State, Query, Event>(
-    query: @escaping (State) -> Set<Query>,
-    effects: @escaping (Query) -> Signal<Event>
+    query: @escaping @Sendable (State) -> Set<Query>,
+    effects: @escaping @Sendable (Query) -> Signal<Event>
     ) -> (Driver<State>) -> Signal<Event> {
     return { (state: Driver<State>) -> Signal<Event> in
         let observableSchedulerContext = ObservableSchedulerContext<State>(
@@ -314,7 +314,7 @@ public class Bindings<Event>: Disposable {
 /**
  Bi-directional binding of a system State to external state machine and events from it.
  */
-public func bind<State, Event>(_ bindings: @escaping (ObservableSchedulerContext<State>) -> (Bindings<Event>)) -> (ObservableSchedulerContext<State>) -> Observable<Event> {
+public func bind<State, Event>(_ bindings: @escaping @Sendable (ObservableSchedulerContext<State>) -> (Bindings<Event>)) -> @Sendable (ObservableSchedulerContext<State>) -> Observable<Event> {
     return { (state: ObservableSchedulerContext<State>) -> Observable<Event> in
         return Observable<Event>.using({ () -> Bindings<Event> in
             return bindings(state)
@@ -329,7 +329,7 @@ public func bind<State, Event>(_ bindings: @escaping (ObservableSchedulerContext
  Bi-directional binding of a system State to external state machine and events from it.
  Strongify owner.
  */
-public func bind<State, Event, WeakOwner>(_ owner: WeakOwner, _ bindings: @escaping (WeakOwner, ObservableSchedulerContext<State>) -> (Bindings<Event>))
+public func bind<State, Event, WeakOwner>(_ owner: WeakOwner, _ bindings: @escaping @Sendable (WeakOwner, ObservableSchedulerContext<State>) -> (Bindings<Event>))
     -> (ObservableSchedulerContext<State>) -> Observable<Event> where WeakOwner: AnyObject {
         return bind(bindingsStrongify(owner, bindings))
 }
@@ -337,7 +337,7 @@ public func bind<State, Event, WeakOwner>(_ owner: WeakOwner, _ bindings: @escap
 /**
  Bi-directional binding of a system State to external state machine and events from it.
  */
-public func bind<State, Event>(_ bindings: @escaping (Driver<State>) -> (Bindings<Event>)) -> (Driver<State>) -> Signal<Event> {
+public func bind<State, Event>(_ bindings: @escaping @Sendable (Driver<State>) -> (Bindings<Event>)) -> @Sendable (Driver<State>) -> Signal<Event> {
     return { (state: Driver<State>) -> Signal<Event> in
         return Observable<Event>.using({ () -> Bindings<Event> in
             return bindings(state)
@@ -354,12 +354,13 @@ public func bind<State, Event>(_ bindings: @escaping (Driver<State>) -> (Binding
  Bi-directional binding of a system State to external state machine and events from it.
  Strongify owner.
  */
-public func bind<State, Event, WeakOwner>(_ owner: WeakOwner, _ bindings: @escaping (WeakOwner, Driver<State>) -> (Bindings<Event>))
-    -> (Driver<State>) -> Signal<Event> where WeakOwner: AnyObject {
+public func bind<State, Event, WeakOwner>(_ owner: WeakOwner, _ bindings: @escaping @Sendable (WeakOwner, Driver<State>) -> (Bindings<Event>))
+    -> @Sendable (Driver<State>) -> Signal<Event> where WeakOwner: AnyObject {
         return bind(bindingsStrongify(owner, bindings))
 }
 
-private func bindingsStrongify<Event, O, WeakOwner>(_ owner: WeakOwner, _ bindings: @escaping (WeakOwner, O) -> (Bindings<Event>))
+@Sendable
+private func bindingsStrongify<Event, O, WeakOwner>(_ owner: WeakOwner, _ bindings: @escaping @Sendable (WeakOwner, O) -> (Bindings<Event>))
     -> (O) -> (Bindings<Event>) where WeakOwner: AnyObject {
         return { [weak owner] state -> Bindings<Event> in
             guard let strongOwner = owner else {
diff --git a/RxExample/RxExample/Observable+Extensions.swift b/RxExample/RxExample/Observable+Extensions.swift
index 035702166..c0fe651e5 100644
--- a/RxExample/RxExample/Observable+Extensions.swift
+++ b/RxExample/RxExample/Observable+Extensions.swift
@@ -30,7 +30,7 @@ extension ObservableType where Element == Any {
      */
     public static func system<State, Event>(
         initialState: State,
-        reduce: @escaping (State, Event) -> State,
+        reduce: @escaping @Sendable (State, Event) -> State,
         scheduler: ImmediateSchedulerType,
         scheduledFeedback: [Feedback<State, Event>]
         ) -> Observable<State> {
@@ -61,7 +61,7 @@ extension ObservableType where Element == Any {
 
     public static func system<State, Event>(
         initialState: State,
-        reduce: @escaping (State, Event) -> State,
+        reduce: @escaping @Sendable (State, Event) -> State,
         scheduler: ImmediateSchedulerType,
         scheduledFeedback: Feedback<State, Event>...
         ) -> Observable<State> {
@@ -86,7 +86,7 @@ extension SharedSequenceConvertibleType where Element == Any, SharingStrategy ==
      */
     public static func system<State, Event>(
             initialState: State,
-            reduce: @escaping (State, Event) -> State,
+            reduce: @escaping @Sendable (State, Event) -> State,
             feedback: [Feedback<State, Event>]
         ) -> Driver<State> {
         let observableFeedbacks: [(ObservableSchedulerContext<State>) -> Observable<Event>] = feedback.map { feedback in
@@ -107,7 +107,7 @@ extension SharedSequenceConvertibleType where Element == Any, SharingStrategy ==
 
     public static func system<State, Event>(
                 initialState: State,
-                reduce: @escaping (State, Event) -> State,
+                reduce: @escaping @Sendable (State, Event) -> State,
                 feedback: Feedback<State, Event>...
         ) -> Driver<State> {
         system(initialState: initialState, reduce: reduce, feedback: feedback)
diff --git a/RxExample/RxExample/Services/ActivityIndicator.swift b/RxExample/RxExample/Services/ActivityIndicator.swift
index 54e47ff95..101943f46 100644
--- a/RxExample/RxExample/Services/ActivityIndicator.swift
+++ b/RxExample/RxExample/Services/ActivityIndicator.swift
@@ -13,7 +13,7 @@ private struct ActivityToken<E> : ObservableConvertibleType, Disposable {
     private let _source: Observable<E>
     private let _dispose: Cancelable
 
-    init(source: Observable<E>, disposeAction: @escaping () -> Void) {
+    init(source: Observable<E>, disposeAction: @escaping @Sendable () -> Void) {
         _source = source
         _dispose = Disposables.create(with: disposeAction)
     }
@@ -33,7 +33,7 @@ Enables monitoring of sequence computation.
 If there is at least one sequence computation in progress, `true` will be sent.
 When all activities complete `false` will be sent.
 */
-public class ActivityIndicator : SharedSequenceConvertibleType {
+public class ActivityIndicator : SharedSequenceConvertibleType, @unchecked Sendable {
     public typealias Element = Bool
     public typealias SharingStrategy = DriverSharingStrategy
 
@@ -55,13 +55,15 @@ public class ActivityIndicator : SharedSequenceConvertibleType {
             return t.asObservable()
         }
     }
-
+    
+    @Sendable
     private func increment() {
         _lock.lock()
         _relay.accept(_relay.value + 1)
         _lock.unlock()
     }
-
+    
+    @Sendable
     private func decrement() {
         _lock.lock()
         _relay.accept(_relay.value - 1)
diff --git a/RxExample/RxExample/Services/GeolocationService.swift b/RxExample/RxExample/Services/GeolocationService.swift
index 18ebea627..cf0c5b607 100644
--- a/RxExample/RxExample/Services/GeolocationService.swift
+++ b/RxExample/RxExample/Services/GeolocationService.swift
@@ -13,8 +13,8 @@ import RxCocoa
 class GeolocationService {
     
     static let instance = GeolocationService()
-    private (set) var authorized: Driver<Bool>
-    private (set) var location: Driver<CLLocationCoordinate2D>
+    private(set) var authorized: Driver<Bool>
+    private(set) var location: Driver<CLLocationCoordinate2D>
     
     private let locationManager = CLLocationManager()
     
diff --git a/RxExample/RxExample/Services/UIImageView+DownloadableImage.swift b/RxExample/RxExample/Services/UIImageView+DownloadableImage.swift
index c800eba08..a92a56a1b 100644
--- a/RxExample/RxExample/Services/UIImageView+DownloadableImage.swift
+++ b/RxExample/RxExample/Services/UIImageView+DownloadableImage.swift
@@ -20,19 +20,21 @@ extension Reactive where Base: UIImageView {
 
     func downloadableImageAnimated(_ transitionType: String?) -> Binder<DownloadableImage> {
         return Binder(base) { imageView, image in
-            for subview in imageView.subviews {
-                subview.removeFromSuperview()
-            }
-            switch image {
-            case .content(let image):
-                (imageView as UIImageView).rx.image.on(.next(image))
-            case .offlinePlaceholder:
-                let label = UILabel(frame: imageView.bounds)
-                label.textAlignment = .center
-                label.font = UIFont.systemFont(ofSize: 35)
-                label.text = "⚠️"
-                imageView.addSubview(label)
-            }
+            MainScheduler.assumeMainActor(execute: {
+                for subview in imageView.subviews {
+                    subview.removeFromSuperview()
+                }
+                switch image {
+                case .content(let image):
+                    (imageView as UIImageView).rx.image.on(.next(image))
+                case .offlinePlaceholder:
+                    let label = UILabel(frame: imageView.bounds)
+                    label.textAlignment = .center
+                    label.font = UIFont.systemFont(ofSize: 35)
+                    label.text = "⚠️"
+                    imageView.addSubview(label)
+                }
+            })
         }
     }
 }
diff --git a/RxSwift/AnyObserver.swift b/RxSwift/AnyObserver.swift
index e92cc816e..b54ce8ca1 100644
--- a/RxSwift/AnyObserver.swift
+++ b/RxSwift/AnyObserver.swift
@@ -11,7 +11,7 @@
 /// Forwards operations to an arbitrary underlying observer with the same `Element` type, hiding the specifics of the underlying observer type.
 public struct AnyObserver<Element> : ObserverType {
     /// Anonymous event handler type.
-    public typealias EventHandler = (Event<Element>) -> Void
+    public typealias EventHandler = @Sendable (Event<Element>) -> Void
 
     private let observer: EventHandler
 
@@ -61,7 +61,7 @@ extension ObserverType {
     /// Each event sent to result observer is transformed and sent to `self`.
     ///
     /// - returns: observer that transforms events.
-    public func mapObserver<Result>(_ transform: @escaping (Result) throws -> Element) -> AnyObserver<Result> {
+    public func mapObserver<Result>(_ transform: @escaping @Sendable (Result) throws -> Element) -> AnyObserver<Result> {
         AnyObserver { e in
             self.on(e.map(transform))
         }
diff --git a/RxSwift/Binder.swift b/RxSwift/Binder.swift
index 1aae09592..c2c9349c4 100644
--- a/RxSwift/Binder.swift
+++ b/RxSwift/Binder.swift
@@ -15,18 +15,18 @@
  
  By default it binds elements on main scheduler.
  */
-public struct Binder<Value>: ObserverType {
+public struct Binder<Value>: ObserverType, @unchecked Sendable {
     public typealias Element = Value
     
-    private let binding: (Event<Value>) -> Void
+    private let binding: @Sendable (Event<Value>) -> Void
 
     /// Initializes `Binder`
     ///
     /// - parameter target: Target object.
     /// - parameter scheduler: Scheduler used to bind the events.
     /// - parameter binding: Binding logic.
-    public init<Target: AnyObject>(_ target: Target, scheduler: ImmediateSchedulerType = MainScheduler(), binding: @escaping (Target, Value) -> Void) {
-        weak var weakTarget = target
+    public init<Target: AnyObject>(_ target: Target, scheduler: ImmediateSchedulerType = MainScheduler(), binding: @escaping @Sendable (Target, Value) -> Void) {
+        nonisolated(unsafe) weak var weakTarget = target
 
         self.binding = { event in
             switch event {
@@ -46,6 +46,7 @@ public struct Binder<Value>: ObserverType {
     }
 
     /// Binds next element to owner view as described in `binding`.
+    @Sendable
     public func on(_ event: Event<Value>) {
         self.binding(event)
     }
diff --git a/RxSwift/Concurrency/AsyncLock.swift b/RxSwift/Concurrency/AsyncLock.swift
index 6bee59c11..3f0b2d11b 100644
--- a/RxSwift/Concurrency/AsyncLock.swift
+++ b/RxSwift/Concurrency/AsyncLock.swift
@@ -19,10 +19,11 @@ That means that enqueued work could possibly be executed later on a different th
 final class AsyncLock<I: InvocableType>
     : Disposable
     , Lock
-    , SynchronizedDisposeType {
-    typealias Action = () -> Void
+    , SynchronizedDisposeType
+    , @unchecked Sendable {
+    typealias Action = @Sendable () -> Void
     
-    private var _lock = SpinLock()
+    nonisolated(unsafe) private var _lock = SpinLock()
     
     private var queue: Queue<I> = Queue(capacity: 0)
 
diff --git a/RxSwift/Disposable.swift b/RxSwift/Disposable.swift
index b79c77a75..9e26911df 100644
--- a/RxSwift/Disposable.swift
+++ b/RxSwift/Disposable.swift
@@ -7,7 +7,7 @@
 //
 
 /// Represents a disposable resource.
-public protocol Disposable {
+public protocol Disposable: Sendable {
     /// Dispose resource.
     func dispose()
 }
diff --git a/RxSwift/Disposables/AnonymousDisposable.swift b/RxSwift/Disposables/AnonymousDisposable.swift
index 591aafa5e..4f008e01b 100644
--- a/RxSwift/Disposables/AnonymousDisposable.swift
+++ b/RxSwift/Disposables/AnonymousDisposable.swift
@@ -9,8 +9,8 @@
 /// Represents an Action-based disposable.
 ///
 /// When dispose method is called, disposal action will be dereferenced.
-private final class AnonymousDisposable : DisposeBase, Cancelable {
-    public typealias DisposeAction = () -> Void
+private final class AnonymousDisposable : DisposeBase, Cancelable, @unchecked Sendable {
+    public typealias DisposeAction = @Sendable () -> Void
 
     private let disposed = AtomicInt(0)
     private var disposeAction: DisposeAction?
@@ -52,7 +52,7 @@ extension Disposables {
     /// Constructs a new disposable with the given action used for disposal.
     ///
     /// - parameter dispose: Disposal action which will be run upon calling `dispose`.
-    public static func create(with dispose: @escaping () -> Void) -> Cancelable {
+    public static func create(with dispose: @escaping @Sendable () -> Void) -> Cancelable {
         AnonymousDisposable(disposeAction: dispose)
     }
 
diff --git a/RxSwift/Disposables/BinaryDisposable.swift b/RxSwift/Disposables/BinaryDisposable.swift
index a3d493708..1e727e569 100644
--- a/RxSwift/Disposables/BinaryDisposable.swift
+++ b/RxSwift/Disposables/BinaryDisposable.swift
@@ -7,7 +7,7 @@
 //
 
 /// Represents two disposable resources that are disposed together.
-private final class BinaryDisposable : DisposeBase, Cancelable {
+private final class BinaryDisposable : DisposeBase, Cancelable, @unchecked Sendable {
 
     private let disposed = AtomicInt(0)
 
diff --git a/RxSwift/Disposables/CompositeDisposable.swift b/RxSwift/Disposables/CompositeDisposable.swift
index bb4efe6ac..66ca6005c 100644
--- a/RxSwift/Disposables/CompositeDisposable.swift
+++ b/RxSwift/Disposables/CompositeDisposable.swift
@@ -7,7 +7,7 @@
 //
 
 /// Represents a group of disposable resources that are disposed together.
-public final class CompositeDisposable : DisposeBase, Cancelable {
+public final class CompositeDisposable : DisposeBase, Cancelable, @unchecked Sendable {
     /// Key used to remove disposable from composite disposable
     public struct DisposeKey {
         fileprivate let key: BagKey
diff --git a/RxSwift/Disposables/DisposeBag.swift b/RxSwift/Disposables/DisposeBag.swift
index 1a673bcce..36eb8e8f8 100644
--- a/RxSwift/Disposables/DisposeBag.swift
+++ b/RxSwift/Disposables/DisposeBag.swift
@@ -27,7 +27,7 @@ or create a new one in its place.
 
 In case explicit disposal is necessary, there is also `CompositeDisposable`.
 */
-public final class DisposeBag: DisposeBase {
+public final class DisposeBag: DisposeBase, @unchecked Sendable {
     
     private var lock = SpinLock()
     
diff --git a/RxSwift/Disposables/DisposeBase.swift b/RxSwift/Disposables/DisposeBase.swift
index 0d4b2fb7f..7102574b7 100644
--- a/RxSwift/Disposables/DisposeBase.swift
+++ b/RxSwift/Disposables/DisposeBase.swift
@@ -7,7 +7,7 @@
 //
 
 /// Base class for all disposables.
-public class DisposeBase {
+public class DisposeBase: @unchecked Sendable {
     init() {
 #if TRACE_RESOURCES
     _ = Resources.incrementTotal()
diff --git a/RxSwift/Disposables/RefCountDisposable.swift b/RxSwift/Disposables/RefCountDisposable.swift
index a59f7789d..50edc9419 100644
--- a/RxSwift/Disposables/RefCountDisposable.swift
+++ b/RxSwift/Disposables/RefCountDisposable.swift
@@ -7,7 +7,7 @@
 //
 
 /// Represents a disposable resource that only disposes its underlying disposable resource when all dependent disposable objects have been disposed.
-public final class RefCountDisposable : DisposeBase, Cancelable {
+public final class RefCountDisposable : DisposeBase, Cancelable, @unchecked Sendable {
     private var lock = SpinLock()
     private var disposable = nil as Disposable?
     private var primaryDisposed = false
@@ -93,7 +93,7 @@ public final class RefCountDisposable : DisposeBase, Cancelable {
     }
 }
 
-internal final class RefCountInnerDisposable: DisposeBase, Disposable
+internal final class RefCountInnerDisposable: DisposeBase, Disposable, @unchecked Sendable
 {
     private let parent: RefCountDisposable
     private let isDisposed = AtomicInt(0)
diff --git a/RxSwift/Disposables/ScheduledDisposable.swift b/RxSwift/Disposables/ScheduledDisposable.swift
index 2cf997bca..5bb072d7b 100644
--- a/RxSwift/Disposables/ScheduledDisposable.swift
+++ b/RxSwift/Disposables/ScheduledDisposable.swift
@@ -6,13 +6,13 @@
 //  Copyright © 2015 Krunoslav Zaher. All rights reserved.
 //
 
-private let disposeScheduledDisposable: (ScheduledDisposable) -> Disposable = { sd in
+private let disposeScheduledDisposable: @Sendable (ScheduledDisposable) -> Disposable = { sd in
     sd.disposeInner()
     return Disposables.create()
 }
 
 /// Represents a disposable resource whose disposal invocation will be scheduled on the specified scheduler.
-public final class ScheduledDisposable : Cancelable {
+public final class ScheduledDisposable : Cancelable, @unchecked Sendable {
     public let scheduler: ImmediateSchedulerType
 
     private let disposed = AtomicInt(0)
diff --git a/RxSwift/Disposables/SerialDisposable.swift b/RxSwift/Disposables/SerialDisposable.swift
index ef4690d32..77d29d859 100644
--- a/RxSwift/Disposables/SerialDisposable.swift
+++ b/RxSwift/Disposables/SerialDisposable.swift
@@ -7,7 +7,7 @@
 //
 
 /// Represents a disposable resource whose underlying disposable resource can be replaced by another disposable resource, causing automatic disposal of the previous underlying disposable resource.
-public final class SerialDisposable : DisposeBase, Cancelable {
+public final class SerialDisposable : DisposeBase, Cancelable, @unchecked Sendable {
     private var lock = SpinLock()
     
     // state
diff --git a/RxSwift/Disposables/SingleAssignmentDisposable.swift b/RxSwift/Disposables/SingleAssignmentDisposable.swift
index 4a5fb8662..8e49e9b56 100644
--- a/RxSwift/Disposables/SingleAssignmentDisposable.swift
+++ b/RxSwift/Disposables/SingleAssignmentDisposable.swift
@@ -11,7 +11,7 @@ Represents a disposable resource which only allows a single assignment of its un
 
 If an underlying disposable resource has already been set, future attempts to set the underlying disposable resource will throw an exception.
 */
-public final class SingleAssignmentDisposable : DisposeBase, Cancelable {
+public final class SingleAssignmentDisposable : DisposeBase, Cancelable, @unchecked Sendable {
 
     private struct DisposeState: OptionSet {
         let rawValue: Int32
diff --git a/RxSwift/Disposables/SubscriptionDisposable.swift b/RxSwift/Disposables/SubscriptionDisposable.swift
index a406c84cb..f85b6febd 100644
--- a/RxSwift/Disposables/SubscriptionDisposable.swift
+++ b/RxSwift/Disposables/SubscriptionDisposable.swift
@@ -6,7 +6,7 @@
 //  Copyright © 2015 Krunoslav Zaher. All rights reserved.
 //
 
-struct SubscriptionDisposable<T: SynchronizedUnsubscribeType> : Disposable {
+struct SubscriptionDisposable<T: SynchronizedUnsubscribeType> : Disposable, @unchecked Sendable {
     private let key: T.DisposeKey
     private weak var owner: T?
 
diff --git a/RxSwift/GroupedObservable.swift b/RxSwift/GroupedObservable.swift
index c4ac44628..ae11142c8 100644
--- a/RxSwift/GroupedObservable.swift
+++ b/RxSwift/GroupedObservable.swift
@@ -36,7 +36,7 @@
 /// next(Banana)
 /// next(Blueberry)
 /// ```
-public struct GroupedObservable<Key, Element> : ObservableType {
+public struct GroupedObservable<Key, Element> : ObservableType, @unchecked Sendable {
     /// The key associated with this grouped observable sequence.
     /// All elements emitted by this observable share this common key.
     public let key: Key
diff --git a/RxSwift/ImmediateSchedulerType.swift b/RxSwift/ImmediateSchedulerType.swift
index 954fbf04b..f6acb0368 100644
--- a/RxSwift/ImmediateSchedulerType.swift
+++ b/RxSwift/ImmediateSchedulerType.swift
@@ -7,7 +7,7 @@
 //
 
 /// Represents an object that immediately schedules units of work.
-public protocol ImmediateSchedulerType {
+public protocol ImmediateSchedulerType: Sendable {
     /**
     Schedules an action to be executed immediately.
     
@@ -15,7 +15,7 @@ public protocol ImmediateSchedulerType {
     - parameter action: Action to be executed.
     - returns: The disposable object used to cancel the scheduled action (best effort).
     */
-    func schedule<StateType>(_ state: StateType, action: @escaping (StateType) -> Disposable) -> Disposable
+    func schedule<StateType>(_ state: StateType, action: @escaping @Sendable (StateType) -> Disposable) -> Disposable
 }
 
 extension ImmediateSchedulerType {
@@ -26,7 +26,7 @@ extension ImmediateSchedulerType {
     - parameter action: Action to execute recursively. The last parameter passed to the action is used to trigger recursive scheduling of the action, passing in recursive invocation state.
     - returns: The disposable object used to cancel the scheduled action (best effort).
     */
-    public func scheduleRecursive<State>(_ state: State, action: @escaping (_ state: State, _ recurse: (State) -> Void) -> Void) -> Disposable {
+    public func scheduleRecursive<State>(_ state: State, action: @escaping @Sendable (_ state: State, _ recurse: (State) -> Void) -> Void) -> Disposable {
         let recursiveScheduler = RecursiveImmediateScheduler(action: action, scheduler: self)
         
         recursiveScheduler.schedule(state)
diff --git a/RxSwift/Observable+Concurrency.swift b/RxSwift/Observable+Concurrency.swift
index af3ec72bc..f086c3a81 100644
--- a/RxSwift/Observable+Concurrency.swift
+++ b/RxSwift/Observable+Concurrency.swift
@@ -27,7 +27,7 @@ public extension ObservableConvertibleType {
     /// ```
     var values: AsyncThrowingStream<Element, Error> {
         AsyncThrowingStream<Element, Error> { continuation in
-            var isFinished = false
+            nonisolated(unsafe) var isFinished = false
             let disposable = asObservable().subscribe(
                 onNext: { value in continuation.yield(value) },
                 onError: { error in
diff --git a/RxSwift/Observable.swift b/RxSwift/Observable.swift
index 7a9221f0b..4122ff69b 100644
--- a/RxSwift/Observable.swift
+++ b/RxSwift/Observable.swift
@@ -12,7 +12,7 @@
 
 public typealias RxObservable<Element> = RxSwift.Observable<Element>
 
-public class Observable<Element> : ObservableType {
+public class Observable<Element> : ObservableType, @unchecked Sendable {
     init() {
 #if TRACE_RESOURCES
         _ = Resources.incrementTotal()
diff --git a/RxSwift/ObservableConvertibleType.swift b/RxSwift/ObservableConvertibleType.swift
index 0f56a8165..b3a2df529 100644
--- a/RxSwift/ObservableConvertibleType.swift
+++ b/RxSwift/ObservableConvertibleType.swift
@@ -7,7 +7,7 @@
 //
 
 /// Type that can be converted to observable sequence (`Observable<Element>`).
-public protocol ObservableConvertibleType {
+public protocol ObservableConvertibleType: Sendable {
     /// Type of elements in sequence.
     associatedtype Element
 
diff --git a/RxSwift/ObservableType+Extensions.swift b/RxSwift/ObservableType+Extensions.swift
index ac850c3ba..71bae2c13 100644
--- a/RxSwift/ObservableType+Extensions.swift
+++ b/RxSwift/ObservableType+Extensions.swift
@@ -17,7 +17,7 @@ extension ObservableType {
      - parameter on: Action to invoke for each event in the observable sequence.
      - returns: Subscription object used to unsubscribe from the observable sequence.
      */
-    public func subscribe(_ on: @escaping (Event<Element>) -> Void) -> Disposable {
+    public func subscribe(_ on: @escaping @Sendable (Event<Element>) -> Void) -> Disposable {
         let observer = AnonymousObserver { e in
             on(e)
         }
@@ -41,10 +41,10 @@ extension ObservableType {
      */
     public func subscribe<Object: AnyObject>(
         with object: Object,
-        onNext: ((Object, Element) -> Void)? = nil,
-        onError: ((Object, Swift.Error) -> Void)? = nil,
-        onCompleted: ((Object) -> Void)? = nil,
-        onDisposed: ((Object) -> Void)? = nil
+        onNext: (@Sendable (Object, Element) -> Void)? = nil,
+        onError: (@Sendable (Object, Swift.Error) -> Void)? = nil,
+        onCompleted: (@Sendable (Object) -> Void)? = nil,
+        onDisposed: (@Sendable (Object) -> Void)? = nil
     ) -> Disposable {
         subscribe(
             onNext: { [weak object] in
@@ -77,10 +77,10 @@ extension ObservableType {
      - returns: Subscription object used to unsubscribe from the observable sequence.
      */
     public func subscribe(
-        onNext: ((Element) -> Void)? = nil,
-        onError: ((Swift.Error) -> Void)? = nil,
-        onCompleted: (() -> Void)? = nil,
-        onDisposed: (() -> Void)? = nil
+        onNext: (@Sendable (Element) -> Void)? = nil,
+        onError: (@Sendable (Swift.Error) -> Void)? = nil,
+        onCompleted: (@Sendable () -> Void)? = nil,
+        onDisposed: (@Sendable () -> Void)? = nil
     ) -> Disposable {
             let disposable: Disposable
             
@@ -130,8 +130,8 @@ extension ObservableType {
 import Foundation
 
 extension Hooks {
-    public typealias DefaultErrorHandler = (_ subscriptionCallStack: [String], _ error: Error) -> Void
-    public typealias CustomCaptureSubscriptionCallstack = () -> [String]
+    public typealias DefaultErrorHandler = @Sendable (_ subscriptionCallStack: [String], _ error: Error) -> Void
+    public typealias CustomCaptureSubscriptionCallstack = @Sendable () -> [String]
 
     private static let lock = RecursiveLock()
     private static var _defaultErrorHandler: DefaultErrorHandler = { subscriptionCallStack, error in
diff --git a/RxSwift/Observables/AddRef.swift b/RxSwift/Observables/AddRef.swift
index a96dfcb03..a1d076579 100644
--- a/RxSwift/Observables/AddRef.swift
+++ b/RxSwift/Observables/AddRef.swift
@@ -6,7 +6,7 @@
 //  Copyright © 2015 Krunoslav Zaher. All rights reserved.
 //
 
-final class AddRefSink<Observer: ObserverType> : Sink<Observer>, ObserverType {
+final class AddRefSink<Observer: ObserverType> : Sink<Observer>, ObserverType, @unchecked Sendable {
     typealias Element = Observer.Element 
     
     override init(observer: Observer, cancel: Cancelable) {
@@ -24,7 +24,7 @@ final class AddRefSink<Observer: ObserverType> : Sink<Observer>, ObserverType {
     }
 }
 
-final class AddRef<Element> : Producer<Element> {
+final class AddRef<Element> : Producer<Element>, @unchecked Sendable {
     
     private let source: Observable<Element>
     private let refCount: RefCountDisposable
diff --git a/RxSwift/Observables/Amb.swift b/RxSwift/Observables/Amb.swift
index efc17a8d9..78209e9be 100644
--- a/RxSwift/Observables/Amb.swift
+++ b/RxSwift/Observables/Amb.swift
@@ -49,11 +49,11 @@ final private class AmbObserver<Observer: ObserverType>: ObserverType {
     typealias Element = Observer.Element 
     typealias Parent = AmbSink<Observer>
     typealias This = AmbObserver<Observer>
-    typealias Sink = (This, Event<Element>) -> Void
+    typealias Sink = @Sendable (This, Event<Element>) -> Void
     
     private let parent: Parent
-    fileprivate var sink: Sink
-    fileprivate var cancel: Disposable
+    nonisolated(unsafe) fileprivate var sink: Sink
+    nonisolated(unsafe) fileprivate var cancel: Disposable
     
     init(parent: Parent, cancel: Disposable, sink: @escaping Sink) {
 #if TRACE_RESOURCES
@@ -79,7 +79,7 @@ final private class AmbObserver<Observer: ObserverType>: ObserverType {
     }
 }
 
-final private class AmbSink<Observer: ObserverType>: Sink<Observer> {
+final private class AmbSink<Observer: ObserverType>: Sink<Observer>, @unchecked Sendable {
     typealias Element = Observer.Element
     typealias Parent = Amb<Element>
     typealias AmbObserverType = AmbObserver<Observer>
@@ -100,7 +100,7 @@ final private class AmbSink<Observer: ObserverType>: Sink<Observer> {
         let subscription2 = SingleAssignmentDisposable()
         let disposeAll = Disposables.create(subscription1, subscription2)
         
-        let forwardEvent = { (o: AmbObserverType, event: Event<Element>) -> Void in
+        let forwardEvent = { @Sendable (o: AmbObserverType, event: Event<Element>) -> Void in
             self.forwardOn(event)
             if event.isStopEvent {
                 self.dispose()
@@ -140,7 +140,7 @@ final private class AmbSink<Observer: ObserverType>: Sink<Observer> {
     }
 }
 
-final private class Amb<Element>: Producer<Element> {
+final private class Amb<Element>: Producer<Element>, @unchecked Sendable {
     fileprivate let left: Observable<Element>
     fileprivate let right: Observable<Element>
     
diff --git a/RxSwift/Observables/AsMaybe.swift b/RxSwift/Observables/AsMaybe.swift
index 6fa625784..4dcde701f 100644
--- a/RxSwift/Observables/AsMaybe.swift
+++ b/RxSwift/Observables/AsMaybe.swift
@@ -6,7 +6,7 @@
 //  Copyright © 2017 Krunoslav Zaher. All rights reserved.
 //
 
-private final class AsMaybeSink<Observer: ObserverType> : Sink<Observer>, ObserverType {
+private final class AsMaybeSink<Observer: ObserverType> : Sink<Observer>, ObserverType, @unchecked Sendable {
     typealias Element = Observer.Element
 
     private var element: Event<Element>?
@@ -33,7 +33,7 @@ private final class AsMaybeSink<Observer: ObserverType> : Sink<Observer>, Observ
     }
 }
 
-final class AsMaybe<Element>: Producer<Element> {
+final class AsMaybe<Element>: Producer<Element>, @unchecked Sendable {
     private let source: Observable<Element>
 
     init(source: Observable<Element>) {
diff --git a/RxSwift/Observables/AsSingle.swift b/RxSwift/Observables/AsSingle.swift
index b39932f12..c22a6a694 100644
--- a/RxSwift/Observables/AsSingle.swift
+++ b/RxSwift/Observables/AsSingle.swift
@@ -6,7 +6,7 @@
 //  Copyright © 2017 Krunoslav Zaher. All rights reserved.
 //
 
-private final class AsSingleSink<Observer: ObserverType> : Sink<Observer>, ObserverType {
+private final class AsSingleSink<Observer: ObserverType> : Sink<Observer>, ObserverType, @unchecked Sendable {
     typealias Element = Observer.Element
 
     private var element: Event<Element>?
@@ -36,7 +36,7 @@ private final class AsSingleSink<Observer: ObserverType> : Sink<Observer>, Obser
     }
 }
 
-final class AsSingle<Element>: Producer<Element> {
+final class AsSingle<Element>: Producer<Element>, @unchecked Sendable {
     private let source: Observable<Element>
 
     init(source: Observable<Element>) {
diff --git a/RxSwift/Observables/Buffer.swift b/RxSwift/Observables/Buffer.swift
index 61424e8bf..8d1f4d3f9 100644
--- a/RxSwift/Observables/Buffer.swift
+++ b/RxSwift/Observables/Buffer.swift
@@ -28,7 +28,7 @@ extension ObservableType {
     }
 }
 
-final private class BufferTimeCount<Element>: Producer<[Element]> {
+final private class BufferTimeCount<Element>: Producer<[Element]>, @unchecked Sendable {
     
     fileprivate let timeSpan: RxTimeInterval
     fileprivate let count: Int
@@ -53,7 +53,8 @@ final private class BufferTimeCountSink<Element, Observer: ObserverType>
     : Sink<Observer>
     , LockOwnerType
     , ObserverType
-    , SynchronizedOnType where Observer.Element == [Element] {
+    , SynchronizedOnType
+    , @unchecked Sendable where Observer.Element == [Element] {
     typealias Parent = BufferTimeCount<Element>
     
     private let parent: Parent
diff --git a/RxSwift/Observables/Catch.swift b/RxSwift/Observables/Catch.swift
index 2efd66062..b1046c81d 100644
--- a/RxSwift/Observables/Catch.swift
+++ b/RxSwift/Observables/Catch.swift
@@ -16,7 +16,7 @@ extension ObservableType {
      - parameter handler: Error handler function, producing another observable sequence.
      - returns: An observable sequence containing the source sequence's elements, followed by the elements produced by the handler's resulting observable sequence in case an error occurred.
      */
-    public func `catch`(_ handler: @escaping (Swift.Error) throws -> Observable<Element>)
+    public func `catch`(_ handler: @escaping @Sendable (Swift.Error) throws -> Observable<Element>)
         -> Observable<Element> {
         Catch(source: self.asObservable(), handler: handler)
     }
@@ -30,7 +30,7 @@ extension ObservableType {
      - returns: An observable sequence containing the source sequence's elements, followed by the elements produced by the handler's resulting observable sequence in case an error occurred.
      */
     @available(*, deprecated, renamed: "catch(_:)")
-    public func catchError(_ handler: @escaping (Swift.Error) throws -> Observable<Element>)
+    public func catchError(_ handler: @escaping @Sendable (Swift.Error) throws -> Observable<Element>)
         -> Observable<Element> {
         `catch`(handler)
     }
@@ -145,7 +145,7 @@ final private class CatchSinkProxy<Observer: ObserverType>: ObserverType {
     }
 }
 
-final private class CatchSink<Observer: ObserverType>: Sink<Observer>, ObserverType {
+final private class CatchSink<Observer: ObserverType>: Sink<Observer>, ObserverType, @unchecked Sendable {
     typealias Element = Observer.Element 
     typealias Parent = Catch<Element>
     
@@ -188,8 +188,8 @@ final private class CatchSink<Observer: ObserverType>: Sink<Observer>, ObserverT
     }
 }
 
-final private class Catch<Element>: Producer<Element> {
-    typealias Handler = (Swift.Error) throws -> Observable<Element>
+final private class Catch<Element>: Producer<Element>, @unchecked Sendable {
+    typealias Handler = @Sendable (Swift.Error) throws -> Observable<Element>
     
     fileprivate let source: Observable<Element>
     fileprivate let handler: Handler
@@ -210,7 +210,8 @@ final private class Catch<Element>: Producer<Element> {
 
 final private class CatchSequenceSink<Sequence: Swift.Sequence, Observer: ObserverType>
     : TailRecursiveSink<Sequence, Observer>
-    , ObserverType where Sequence.Element: ObservableConvertibleType, Sequence.Element.Element == Observer.Element {
+    , ObserverType
+    , @unchecked Sendable where Sequence.Element: ObservableConvertibleType, Sequence.Element.Element == Observer.Element {
     typealias Element = Observer.Element
     typealias Parent = CatchSequence<Sequence>
 
@@ -258,7 +259,7 @@ final private class CatchSequenceSink<Sequence: Swift.Sequence, Observer: Observ
     }
 }
 
-final private class CatchSequence<Sequence: Swift.Sequence>: Producer<Sequence.Element.Element> where Sequence.Element: ObservableConvertibleType {
+final private class CatchSequence<Sequence: Swift.Sequence>: Producer<Sequence.Element.Element>, @unchecked Sendable where Sequence.Element: ObservableConvertibleType {
     typealias Element = Sequence.Element.Element
     
     let sources: Sequence
diff --git a/RxSwift/Observables/CombineLatest+Collection.swift b/RxSwift/Observables/CombineLatest+Collection.swift
index b56d050bb..b0df24a6a 100644
--- a/RxSwift/Observables/CombineLatest+Collection.swift
+++ b/RxSwift/Observables/CombineLatest+Collection.swift
@@ -15,7 +15,7 @@ extension ObservableType {
      - parameter resultSelector: Function to invoke whenever any of the sources produces an element.
      - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
      */
-    public static func combineLatest<Collection: Swift.Collection>(_ collection: Collection, resultSelector: @escaping ([Collection.Element.Element]) throws -> Element) -> Observable<Element>
+    public static func combineLatest<Collection: Swift.Collection>(_ collection: Collection, resultSelector: @escaping @Sendable ([Collection.Element.Element]) throws -> Element) -> Observable<Element>
         where Collection.Element: ObservableType {
         CombineLatestCollectionType(sources: collection, resultSelector: resultSelector)
     }
@@ -34,7 +34,7 @@ extension ObservableType {
 }
 
 final class CombineLatestCollectionTypeSink<Collection: Swift.Collection, Observer: ObserverType>
-    : Sink<Observer> where Collection.Element: ObservableConvertibleType {
+    : Sink<Observer>, @unchecked Sendable where Collection.Element: ObservableConvertibleType {
     typealias Result = Observer.Element 
     typealias Parent = CombineLatestCollectionType<Collection, Result>
     typealias SourceElement = Collection.Element.Element
@@ -144,8 +144,8 @@ final class CombineLatestCollectionTypeSink<Collection: Swift.Collection, Observ
     }
 }
 
-final class CombineLatestCollectionType<Collection: Swift.Collection, Result>: Producer<Result> where Collection.Element: ObservableConvertibleType {
-    typealias ResultSelector = ([Collection.Element.Element]) throws -> Result
+final class CombineLatestCollectionType<Collection: Swift.Collection, Result>: Producer<Result>, @unchecked Sendable where Collection.Element: ObservableConvertibleType {
+    typealias ResultSelector = @Sendable ([Collection.Element.Element]) throws -> Result
     
     let sources: Collection
     let resultSelector: ResultSelector
diff --git a/RxSwift/Observables/CombineLatest+arity.swift b/RxSwift/Observables/CombineLatest+arity.swift
index e69bbab4a..983827dab 100644
--- a/RxSwift/Observables/CombineLatest+arity.swift
+++ b/RxSwift/Observables/CombineLatest+arity.swift
@@ -21,7 +21,7 @@ extension ObservableType {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func combineLatest<O1: ObservableType, O2: ObservableType>
-        (_ source1: O1, _ source2: O2, resultSelector: @escaping (O1.Element, O2.Element) throws -> Element)
+        (_ source1: O1, _ source2: O2, resultSelector: @escaping @Sendable (O1.Element, O2.Element) throws -> Element)
             -> Observable<Element> {
         return CombineLatest2(
             source1: source1.asObservable(), source2: source2.asObservable(),
@@ -48,7 +48,7 @@ extension ObservableType where Element == Any {
     }
 }
 
-final class CombineLatestSink2_<E1, E2, Observer: ObserverType> : CombineLatestSink<Observer> {
+final class CombineLatestSink2_<E1, E2, Observer: ObserverType> : CombineLatestSink<Observer>, @unchecked Sendable {
     typealias Result = Observer.Element
     typealias Parent = CombineLatest2<E1, E2, Result>
 
@@ -83,8 +83,8 @@ final class CombineLatestSink2_<E1, E2, Observer: ObserverType> : CombineLatestS
     }
 }
 
-final class CombineLatest2<E1, E2, Result> : Producer<Result> {
-    typealias ResultSelector = (E1, E2) throws -> Result
+final class CombineLatest2<E1, E2, Result> : Producer<Result>, @unchecked Sendable {
+    typealias ResultSelector = @Sendable (E1, E2) throws -> Result
 
     let source1: Observable<E1>
     let source2: Observable<E2>
@@ -119,7 +119,7 @@ extension ObservableType {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func combineLatest<O1: ObservableType, O2: ObservableType, O3: ObservableType>
-        (_ source1: O1, _ source2: O2, _ source3: O3, resultSelector: @escaping (O1.Element, O2.Element, O3.Element) throws -> Element)
+        (_ source1: O1, _ source2: O2, _ source3: O3, resultSelector: @escaping @Sendable (O1.Element, O2.Element, O3.Element) throws -> Element)
             -> Observable<Element> {
         return CombineLatest3(
             source1: source1.asObservable(), source2: source2.asObservable(), source3: source3.asObservable(),
@@ -146,7 +146,7 @@ extension ObservableType where Element == Any {
     }
 }
 
-final class CombineLatestSink3_<E1, E2, E3, Observer: ObserverType> : CombineLatestSink<Observer> {
+final class CombineLatestSink3_<E1, E2, E3, Observer: ObserverType> : CombineLatestSink<Observer>, @unchecked Sendable {
     typealias Result = Observer.Element
     typealias Parent = CombineLatest3<E1, E2, E3, Result>
 
@@ -186,8 +186,8 @@ final class CombineLatestSink3_<E1, E2, E3, Observer: ObserverType> : CombineLat
     }
 }
 
-final class CombineLatest3<E1, E2, E3, Result> : Producer<Result> {
-    typealias ResultSelector = (E1, E2, E3) throws -> Result
+final class CombineLatest3<E1, E2, E3, Result> : Producer<Result>, @unchecked Sendable {
+    typealias ResultSelector = @Sendable (E1, E2, E3) throws -> Result
 
     let source1: Observable<E1>
     let source2: Observable<E2>
@@ -224,7 +224,7 @@ extension ObservableType {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func combineLatest<O1: ObservableType, O2: ObservableType, O3: ObservableType, O4: ObservableType>
-        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, resultSelector: @escaping (O1.Element, O2.Element, O3.Element, O4.Element) throws -> Element)
+    (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, resultSelector: @escaping @Sendable (O1.Element, O2.Element, O3.Element, O4.Element) throws -> Element)
             -> Observable<Element> {
         return CombineLatest4(
             source1: source1.asObservable(), source2: source2.asObservable(), source3: source3.asObservable(), source4: source4.asObservable(),
@@ -251,7 +251,7 @@ extension ObservableType where Element == Any {
     }
 }
 
-final class CombineLatestSink4_<E1, E2, E3, E4, Observer: ObserverType> : CombineLatestSink<Observer> {
+final class CombineLatestSink4_<E1, E2, E3, E4, Observer: ObserverType> : CombineLatestSink<Observer>, @unchecked Sendable {
     typealias Result = Observer.Element
     typealias Parent = CombineLatest4<E1, E2, E3, E4, Result>
 
@@ -296,8 +296,8 @@ final class CombineLatestSink4_<E1, E2, E3, E4, Observer: ObserverType> : Combin
     }
 }
 
-final class CombineLatest4<E1, E2, E3, E4, Result> : Producer<Result> {
-    typealias ResultSelector = (E1, E2, E3, E4) throws -> Result
+final class CombineLatest4<E1, E2, E3, E4, Result> : Producer<Result>, @unchecked Sendable {
+    typealias ResultSelector = @Sendable (E1, E2, E3, E4) throws -> Result
 
     let source1: Observable<E1>
     let source2: Observable<E2>
@@ -336,7 +336,7 @@ extension ObservableType {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func combineLatest<O1: ObservableType, O2: ObservableType, O3: ObservableType, O4: ObservableType, O5: ObservableType>
-        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, resultSelector: @escaping (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element) throws -> Element)
+    (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, resultSelector: @escaping @Sendable (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element) throws -> Element)
             -> Observable<Element> {
         return CombineLatest5(
             source1: source1.asObservable(), source2: source2.asObservable(), source3: source3.asObservable(), source4: source4.asObservable(), source5: source5.asObservable(),
@@ -363,7 +363,7 @@ extension ObservableType where Element == Any {
     }
 }
 
-final class CombineLatestSink5_<E1, E2, E3, E4, E5, Observer: ObserverType> : CombineLatestSink<Observer> {
+final class CombineLatestSink5_<E1, E2, E3, E4, E5, Observer: ObserverType> : CombineLatestSink<Observer>, @unchecked Sendable {
     typealias Result = Observer.Element
     typealias Parent = CombineLatest5<E1, E2, E3, E4, E5, Result>
 
@@ -413,8 +413,8 @@ final class CombineLatestSink5_<E1, E2, E3, E4, E5, Observer: ObserverType> : Co
     }
 }
 
-final class CombineLatest5<E1, E2, E3, E4, E5, Result> : Producer<Result> {
-    typealias ResultSelector = (E1, E2, E3, E4, E5) throws -> Result
+final class CombineLatest5<E1, E2, E3, E4, E5, Result> : Producer<Result>, @unchecked Sendable {
+    typealias ResultSelector = @Sendable (E1, E2, E3, E4, E5) throws -> Result
 
     let source1: Observable<E1>
     let source2: Observable<E2>
@@ -455,7 +455,7 @@ extension ObservableType {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func combineLatest<O1: ObservableType, O2: ObservableType, O3: ObservableType, O4: ObservableType, O5: ObservableType, O6: ObservableType>
-        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, _ source6: O6, resultSelector: @escaping (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element, O6.Element) throws -> Element)
+    (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, _ source6: O6, resultSelector: @escaping @Sendable (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element, O6.Element) throws -> Element)
             -> Observable<Element> {
         return CombineLatest6(
             source1: source1.asObservable(), source2: source2.asObservable(), source3: source3.asObservable(), source4: source4.asObservable(), source5: source5.asObservable(), source6: source6.asObservable(),
@@ -482,7 +482,7 @@ extension ObservableType where Element == Any {
     }
 }
 
-final class CombineLatestSink6_<E1, E2, E3, E4, E5, E6, Observer: ObserverType> : CombineLatestSink<Observer> {
+final class CombineLatestSink6_<E1, E2, E3, E4, E5, E6, Observer: ObserverType> : CombineLatestSink<Observer>, @unchecked Sendable {
     typealias Result = Observer.Element
     typealias Parent = CombineLatest6<E1, E2, E3, E4, E5, E6, Result>
 
@@ -537,8 +537,8 @@ final class CombineLatestSink6_<E1, E2, E3, E4, E5, E6, Observer: ObserverType>
     }
 }
 
-final class CombineLatest6<E1, E2, E3, E4, E5, E6, Result> : Producer<Result> {
-    typealias ResultSelector = (E1, E2, E3, E4, E5, E6) throws -> Result
+final class CombineLatest6<E1, E2, E3, E4, E5, E6, Result> : Producer<Result>, @unchecked Sendable {
+    typealias ResultSelector = @Sendable (E1, E2, E3, E4, E5, E6) throws -> Result
 
     let source1: Observable<E1>
     let source2: Observable<E2>
@@ -581,7 +581,7 @@ extension ObservableType {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func combineLatest<O1: ObservableType, O2: ObservableType, O3: ObservableType, O4: ObservableType, O5: ObservableType, O6: ObservableType, O7: ObservableType>
-        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, _ source6: O6, _ source7: O7, resultSelector: @escaping (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element, O6.Element, O7.Element) throws -> Element)
+    (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, _ source6: O6, _ source7: O7, resultSelector: @escaping @Sendable (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element, O6.Element, O7.Element) throws -> Element)
             -> Observable<Element> {
         return CombineLatest7(
             source1: source1.asObservable(), source2: source2.asObservable(), source3: source3.asObservable(), source4: source4.asObservable(), source5: source5.asObservable(), source6: source6.asObservable(), source7: source7.asObservable(),
@@ -608,7 +608,7 @@ extension ObservableType where Element == Any {
     }
 }
 
-final class CombineLatestSink7_<E1, E2, E3, E4, E5, E6, E7, Observer: ObserverType> : CombineLatestSink<Observer> {
+final class CombineLatestSink7_<E1, E2, E3, E4, E5, E6, E7, Observer: ObserverType> : CombineLatestSink<Observer>, @unchecked Sendable {
     typealias Result = Observer.Element
     typealias Parent = CombineLatest7<E1, E2, E3, E4, E5, E6, E7, Result>
 
@@ -668,8 +668,8 @@ final class CombineLatestSink7_<E1, E2, E3, E4, E5, E6, E7, Observer: ObserverTy
     }
 }
 
-final class CombineLatest7<E1, E2, E3, E4, E5, E6, E7, Result> : Producer<Result> {
-    typealias ResultSelector = (E1, E2, E3, E4, E5, E6, E7) throws -> Result
+final class CombineLatest7<E1, E2, E3, E4, E5, E6, E7, Result> : Producer<Result>, @unchecked Sendable {
+    typealias ResultSelector = @Sendable (E1, E2, E3, E4, E5, E6, E7) throws -> Result
 
     let source1: Observable<E1>
     let source2: Observable<E2>
@@ -714,7 +714,7 @@ extension ObservableType {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func combineLatest<O1: ObservableType, O2: ObservableType, O3: ObservableType, O4: ObservableType, O5: ObservableType, O6: ObservableType, O7: ObservableType, O8: ObservableType>
-        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, _ source6: O6, _ source7: O7, _ source8: O8, resultSelector: @escaping (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element, O6.Element, O7.Element, O8.Element) throws -> Element)
+    (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, _ source6: O6, _ source7: O7, _ source8: O8, resultSelector: @escaping @Sendable (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element, O6.Element, O7.Element, O8.Element) throws -> Element)
             -> Observable<Element> {
         return CombineLatest8(
             source1: source1.asObservable(), source2: source2.asObservable(), source3: source3.asObservable(), source4: source4.asObservable(), source5: source5.asObservable(), source6: source6.asObservable(), source7: source7.asObservable(), source8: source8.asObservable(),
@@ -741,7 +741,7 @@ extension ObservableType where Element == Any {
     }
 }
 
-final class CombineLatestSink8_<E1, E2, E3, E4, E5, E6, E7, E8, Observer: ObserverType> : CombineLatestSink<Observer> {
+final class CombineLatestSink8_<E1, E2, E3, E4, E5, E6, E7, E8, Observer: ObserverType> : CombineLatestSink<Observer>, @unchecked Sendable {
     typealias Result = Observer.Element
     typealias Parent = CombineLatest8<E1, E2, E3, E4, E5, E6, E7, E8, Result>
 
@@ -806,8 +806,8 @@ final class CombineLatestSink8_<E1, E2, E3, E4, E5, E6, E7, E8, Observer: Observ
     }
 }
 
-final class CombineLatest8<E1, E2, E3, E4, E5, E6, E7, E8, Result> : Producer<Result> {
-    typealias ResultSelector = (E1, E2, E3, E4, E5, E6, E7, E8) throws -> Result
+final class CombineLatest8<E1, E2, E3, E4, E5, E6, E7, E8, Result> : Producer<Result>, @unchecked Sendable {
+    typealias ResultSelector = @Sendable (E1, E2, E3, E4, E5, E6, E7, E8) throws -> Result
 
     let source1: Observable<E1>
     let source2: Observable<E2>
diff --git a/RxSwift/Observables/CombineLatest.swift b/RxSwift/Observables/CombineLatest.swift
index caa025640..e278a8288 100644
--- a/RxSwift/Observables/CombineLatest.swift
+++ b/RxSwift/Observables/CombineLatest.swift
@@ -14,8 +14,9 @@ protocol CombineLatestProtocol: AnyObject {
 
 class CombineLatestSink<Observer: ObserverType>
     : Sink<Observer>
-    , CombineLatestProtocol {
-    typealias Element = Observer.Element 
+    , CombineLatestProtocol
+    , @unchecked Sendable {
+    typealias Element = Observer.Element
    
     let lock = RecursiveLock()
 
@@ -93,8 +94,9 @@ class CombineLatestSink<Observer: ObserverType>
 final class CombineLatestObserver<Element>
     : ObserverType
     , LockOwnerType
-    , SynchronizedOnType {
-    typealias ValueSetter = (Element) -> Void
+    , SynchronizedOnType
+    , @unchecked Sendable {
+    typealias ValueSetter = @Sendable (Element) -> Void
     
     private let parent: CombineLatestProtocol
     
diff --git a/RxSwift/Observables/CompactMap.swift b/RxSwift/Observables/CompactMap.swift
index 7dbcdfbe9..a2bc49f3d 100644
--- a/RxSwift/Observables/CompactMap.swift
+++ b/RxSwift/Observables/CompactMap.swift
@@ -15,14 +15,14 @@ extension ObservableType {
      - returns: An observable sequence whose elements are the result of filtering the transform function for each element of the source.
 
      */
-    public func compactMap<Result>(_ transform: @escaping (Element) throws -> Result?)
+    public func compactMap<Result>(_ transform: @escaping @Sendable (Element) throws -> Result?)
         -> Observable<Result> {
         CompactMap(source: self.asObservable(), transform: transform)
     }
 }
 
-final private class CompactMapSink<SourceType, Observer: ObserverType>: Sink<Observer>, ObserverType {
-    typealias Transform = (SourceType) throws -> ResultType?
+final private class CompactMapSink<SourceType, Observer: ObserverType>: Sink<Observer>, ObserverType, @unchecked Sendable {
+    typealias Transform = @Sendable (SourceType) throws -> ResultType?
 
     typealias ResultType = Observer.Element 
     typealias Element = SourceType
@@ -56,8 +56,8 @@ final private class CompactMapSink<SourceType, Observer: ObserverType>: Sink<Obs
     }
 }
 
-final private class CompactMap<SourceType, ResultType>: Producer<ResultType> {
-    typealias Transform = (SourceType) throws -> ResultType?
+final private class CompactMap<SourceType, ResultType>: Producer<ResultType>, @unchecked Sendable {
+    typealias Transform = @Sendable (SourceType) throws -> ResultType?
 
     private let source: Observable<SourceType>
 
diff --git a/RxSwift/Observables/Concat.swift b/RxSwift/Observables/Concat.swift
index b2fb1a2e5..d5e25ca09 100644
--- a/RxSwift/Observables/Concat.swift
+++ b/RxSwift/Observables/Concat.swift
@@ -78,8 +78,9 @@ extension ObservableType {
 
 final private class ConcatSink<Sequence: Swift.Sequence, Observer: ObserverType>
     : TailRecursiveSink<Sequence, Observer>
-    , ObserverType where Sequence.Element: ObservableConvertibleType, Sequence.Element.Element == Observer.Element {
-    typealias Element = Observer.Element 
+    , ObserverType
+    , @unchecked Sendable where Sequence.Element: ObservableConvertibleType, Sequence.Element.Element == Observer.Element {
+    typealias Element = Observer.Element
     
     override init(observer: Observer, cancel: Cancelable) {
         super.init(observer: observer, cancel: cancel)
@@ -111,7 +112,7 @@ final private class ConcatSink<Sequence: Swift.Sequence, Observer: ObserverType>
     }
 }
 
-final private class Concat<Sequence: Swift.Sequence>: Producer<Sequence.Element.Element> where Sequence.Element: ObservableConvertibleType {
+final private class Concat<Sequence: Swift.Sequence>: Producer<Sequence.Element.Element>, @unchecked Sendable where Sequence.Element: ObservableConvertibleType {
     typealias Element = Sequence.Element.Element
     
     fileprivate let sources: Sequence
diff --git a/RxSwift/Observables/Create.swift b/RxSwift/Observables/Create.swift
index ca81442ce..495f8a120 100644
--- a/RxSwift/Observables/Create.swift
+++ b/RxSwift/Observables/Create.swift
@@ -17,12 +17,12 @@ extension ObservableType {
      - parameter subscribe: Implementation of the resulting observable sequence's `subscribe` method.
      - returns: The observable sequence with the specified implementation for the `subscribe` method.
      */
-    public static func create(_ subscribe: @escaping (AnyObserver<Element>) -> Disposable) -> Observable<Element> {
+    public static func create(_ subscribe: @escaping @Sendable (AnyObserver<Element>) -> Disposable) -> Observable<Element> {
         AnonymousObservable(subscribe)
     }
 }
 
-final private class AnonymousObservableSink<Observer: ObserverType>: Sink<Observer>, ObserverType {
+final private class AnonymousObservableSink<Observer: ObserverType>: Sink<Observer>, ObserverType, @unchecked Sendable {
     typealias Element = Observer.Element 
     typealias Parent = AnonymousObservable<Element>
 
@@ -61,8 +61,8 @@ final private class AnonymousObservableSink<Observer: ObserverType>: Sink<Observ
     }
 }
 
-final private class AnonymousObservable<Element>: Producer<Element> {
-    typealias SubscribeHandler = (AnyObserver<Element>) -> Disposable
+final private class AnonymousObservable<Element>: Producer<Element>, @unchecked Sendable {
+    typealias SubscribeHandler = @Sendable (AnyObserver<Element>) -> Disposable
 
     let subscribeHandler: SubscribeHandler
 
diff --git a/RxSwift/Observables/Debounce.swift b/RxSwift/Observables/Debounce.swift
index 581a5cc5e..b8a9132c8 100644
--- a/RxSwift/Observables/Debounce.swift
+++ b/RxSwift/Observables/Debounce.swift
@@ -29,8 +29,9 @@ final private class DebounceSink<Observer: ObserverType>
     : Sink<Observer>
     , ObserverType
     , LockOwnerType
-    , SynchronizedOnType {
-    typealias Element = Observer.Element 
+    , SynchronizedOnType
+    , @unchecked Sendable {
+    typealias Element = Observer.Element
     typealias ParentType = Debounce<Element>
 
     private let parent: ParentType
@@ -87,6 +88,7 @@ final private class DebounceSink<Observer: ObserverType>
         }
     }
 
+    @Sendable
     func propagate(_ currentId: UInt64) -> Disposable {
         self.lock.performLocked {
             let originalValue = self.value
@@ -101,7 +103,7 @@ final private class DebounceSink<Observer: ObserverType>
     }
 }
 
-final private class Debounce<Element>: Producer<Element> {
+final private class Debounce<Element>: Producer<Element>, @unchecked Sendable {
     fileprivate let source: Observable<Element>
     fileprivate let dueTime: RxTimeInterval
     fileprivate let scheduler: SchedulerType
diff --git a/RxSwift/Observables/Debug.swift b/RxSwift/Observables/Debug.swift
index 762e394fc..10e863c5b 100644
--- a/RxSwift/Observables/Debug.swift
+++ b/RxSwift/Observables/Debug.swift
@@ -31,7 +31,7 @@ private func logEvent(_ identifier: String, dateFormat: DateFormatter, content:
     print("\(dateFormat.string(from: Date())): \(identifier) -> \(content)")
 }
 
-final private class DebugSink<Source: ObservableType, Observer: ObserverType>: Sink<Observer>, ObserverType where Observer.Element == Source.Element {
+final private class DebugSink<Source: ObservableType, Observer: ObserverType>: Sink<Observer>, ObserverType, @unchecked Sendable where Observer.Element == Source.Element {
     typealias Element = Observer.Element 
     typealias Parent = Debug<Source>
     
@@ -71,7 +71,7 @@ final private class DebugSink<Source: ObservableType, Observer: ObserverType>: S
     }
 }
 
-final private class Debug<Source: ObservableType>: Producer<Source.Element> {
+final private class Debug<Source: ObservableType>: Producer<Source.Element>, @unchecked Sendable {
     fileprivate let identifier: String
     fileprivate let trimOutput: Bool
     private let source: Source
diff --git a/RxSwift/Observables/DefaultIfEmpty.swift b/RxSwift/Observables/DefaultIfEmpty.swift
index 8d133d8f8..356bdbf33 100644
--- a/RxSwift/Observables/DefaultIfEmpty.swift
+++ b/RxSwift/Observables/DefaultIfEmpty.swift
@@ -21,7 +21,7 @@ extension ObservableType {
     }
 }
 
-final private class DefaultIfEmptySink<Observer: ObserverType>: Sink<Observer>, ObserverType {
+final private class DefaultIfEmptySink<Observer: ObserverType>: Sink<Observer>, ObserverType, @unchecked Sendable {
     typealias Element = Observer.Element 
     private let `default`: Element
     private var isEmpty = true
@@ -49,7 +49,7 @@ final private class DefaultIfEmptySink<Observer: ObserverType>: Sink<Observer>,
     }
 }
 
-final private class DefaultIfEmpty<SourceType>: Producer<SourceType> {
+final private class DefaultIfEmpty<SourceType>: Producer<SourceType>, @unchecked Sendable {
     private let source: Observable<SourceType>
     private let `default`: SourceType
     
diff --git a/RxSwift/Observables/Deferred.swift b/RxSwift/Observables/Deferred.swift
index 51e64d1c0..f86100f04 100644
--- a/RxSwift/Observables/Deferred.swift
+++ b/RxSwift/Observables/Deferred.swift
@@ -15,13 +15,13 @@ extension ObservableType {
      - parameter observableFactory: Observable factory function to invoke for each observer that subscribes to the resulting sequence.
      - returns: An observable sequence whose observers trigger an invocation of the given observable factory function.
      */
-    public static func deferred(_ observableFactory: @escaping () throws -> Observable<Element>)
+    public static func deferred(_ observableFactory: @escaping @Sendable () throws -> Observable<Element>)
         -> Observable<Element> {
         Deferred(observableFactory: observableFactory)
     }
 }
 
-final private class DeferredSink<Source: ObservableType, Observer: ObserverType>: Sink<Observer>, ObserverType where Source.Element == Observer.Element {
+final private class DeferredSink<Source: ObservableType, Observer: ObserverType>: Sink<Observer>, ObserverType, @unchecked Sendable where Source.Element == Observer.Element {
     typealias Element = Observer.Element
     typealias Parent = Deferred<Source>
     
@@ -55,8 +55,8 @@ final private class DeferredSink<Source: ObservableType, Observer: ObserverType>
     }
 }
 
-final private class Deferred<Source: ObservableType>: Producer<Source.Element> {
-    typealias Factory = () throws -> Source
+final private class Deferred<Source: ObservableType>: Producer<Source.Element>, @unchecked Sendable {
+    typealias Factory = @Sendable () throws -> Source
     
     let observableFactory : Factory
     
diff --git a/RxSwift/Observables/Delay.swift b/RxSwift/Observables/Delay.swift
index 9f71c32d0..f15779b17 100644
--- a/RxSwift/Observables/Delay.swift
+++ b/RxSwift/Observables/Delay.swift
@@ -27,8 +27,9 @@ extension ObservableType {
 
 final private class DelaySink<Observer: ObserverType>
     : Sink<Observer>
-    , ObserverType {
-    typealias Element = Observer.Element 
+    , ObserverType
+    , @unchecked Sendable {
+    typealias Element = Observer.Element
     typealias Source = Observable<Element>
     typealias DisposeKey = Bag<Disposable>.KeyType
     
@@ -60,6 +61,7 @@ final private class DelaySink<Observer: ObserverType>
     // scheduler so this process needs to be synchronized somehow.
     //
     // Another complication is that scheduler is potentially concurrent so internal queue is used.
+    @Sendable
     func drainQueue(state: (), scheduler: AnyRecursiveScheduler<()>) {
         self.lock.lock()    
         let hasFailed = self.errorEvent != nil
@@ -155,7 +157,7 @@ final private class DelaySink<Observer: ObserverType>
     }
 }
 
-final private class Delay<Element>: Producer<Element> {
+final private class Delay<Element>: Producer<Element>, @unchecked Sendable {
     private let source: Observable<Element>
     private let dueTime: RxTimeInterval
     private let scheduler: SchedulerType
diff --git a/RxSwift/Observables/DelaySubscription.swift b/RxSwift/Observables/DelaySubscription.swift
index 099c0ddcb..97154f46d 100644
--- a/RxSwift/Observables/DelaySubscription.swift
+++ b/RxSwift/Observables/DelaySubscription.swift
@@ -26,8 +26,9 @@ extension ObservableType {
 }
 
 final private class DelaySubscriptionSink<Observer: ObserverType>
-    : Sink<Observer>, ObserverType {
-    typealias Element = Observer.Element 
+    : Sink<Observer>, ObserverType
+    , @unchecked Sendable {
+    typealias Element = Observer.Element
     
     func on(_ event: Event<Element>) {
         self.forwardOn(event)
@@ -38,7 +39,7 @@ final private class DelaySubscriptionSink<Observer: ObserverType>
     
 }
 
-final private class DelaySubscription<Element>: Producer<Element> {
+final private class DelaySubscription<Element>: Producer<Element>, @unchecked Sendable {
     private let source: Observable<Element>
     private let dueTime: RxTimeInterval
     private let scheduler: SchedulerType
diff --git a/RxSwift/Observables/Dematerialize.swift b/RxSwift/Observables/Dematerialize.swift
index 2ccd54620..8e05c12aa 100644
--- a/RxSwift/Observables/Dematerialize.swift
+++ b/RxSwift/Observables/Dematerialize.swift
@@ -18,7 +18,7 @@ extension ObservableType where Element: EventConvertible {
 
 }
 
-private final class DematerializeSink<T: EventConvertible, Observer: ObserverType>: Sink<Observer>, ObserverType where Observer.Element == T.Element {
+private final class DematerializeSink<T: EventConvertible, Observer: ObserverType>: Sink<Observer>, ObserverType, @unchecked Sendable where Observer.Element == T.Element {
     fileprivate func on(_ event: Event<T>) {
         switch event {
         case .next(let element):
@@ -36,7 +36,7 @@ private final class DematerializeSink<T: EventConvertible, Observer: ObserverTyp
     }
 }
 
-final private class Dematerialize<T: EventConvertible>: Producer<T.Element> {
+final private class Dematerialize<T: EventConvertible>: Producer<T.Element>, @unchecked Sendable {
     private let source: Observable<T>
 
     init(source: Observable<T>) {
diff --git a/RxSwift/Observables/DistinctUntilChanged.swift b/RxSwift/Observables/DistinctUntilChanged.swift
index c127b5aa5..0429fb0f6 100644
--- a/RxSwift/Observables/DistinctUntilChanged.swift
+++ b/RxSwift/Observables/DistinctUntilChanged.swift
@@ -30,7 +30,7 @@ extension ObservableType {
      - parameter keySelector: A function to compute the comparison key for each element.
      - returns: An observable sequence only containing the distinct contiguous elements, based on a computed key value, from the source sequence.
      */
-    public func distinctUntilChanged<Key: Equatable>(_ keySelector: @escaping (Element) throws -> Key)
+    public func distinctUntilChanged<Key: Equatable>(_ keySelector: @escaping @Sendable (Element) throws -> Key)
         -> Observable<Element> {
         self.distinctUntilChanged(keySelector, comparer: { $0 == $1 })
     }
@@ -43,7 +43,7 @@ extension ObservableType {
      - parameter comparer: Equality comparer for computed key values.
      - returns: An observable sequence only containing the distinct contiguous elements, based on `comparer`, from the source sequence.
      */
-    public func distinctUntilChanged(_ comparer: @escaping (Element, Element) throws -> Bool)
+    public func distinctUntilChanged(_ comparer: @escaping @Sendable (Element, Element) throws -> Bool)
         -> Observable<Element> {
         self.distinctUntilChanged({ $0 }, comparer: comparer)
     }
@@ -57,7 +57,7 @@ extension ObservableType {
      - parameter comparer: Equality comparer for computed key values.
      - returns: An observable sequence only containing the distinct contiguous elements, based on a computed key value and the comparer, from the source sequence.
      */
-    public func distinctUntilChanged<K>(_ keySelector: @escaping (Element) throws -> K, comparer: @escaping (K, K) throws -> Bool)
+    public func distinctUntilChanged<K>(_ keySelector: @escaping @Sendable (Element) throws -> K, comparer: @escaping @Sendable (K, K) throws -> Bool)
         -> Observable<Element> {
             return DistinctUntilChanged(source: self.asObservable(), selector: keySelector, comparer: comparer)
     }
@@ -75,7 +75,7 @@ extension ObservableType {
     }
 }
 
-final private class DistinctUntilChangedSink<Observer: ObserverType, Key>: Sink<Observer>, ObserverType {
+final private class DistinctUntilChangedSink<Observer: ObserverType, Key>: Sink<Observer>, ObserverType, @unchecked Sendable {
     typealias Element = Observer.Element 
     
     private let parent: DistinctUntilChanged<Element, Key>
@@ -115,9 +115,9 @@ final private class DistinctUntilChangedSink<Observer: ObserverType, Key>: Sink<
     }
 }
 
-final private class DistinctUntilChanged<Element, Key>: Producer<Element> {
-    typealias KeySelector = (Element) throws -> Key
-    typealias EqualityComparer = (Key, Key) throws -> Bool
+final private class DistinctUntilChanged<Element, Key>: Producer<Element>, @unchecked Sendable {
+    typealias KeySelector = @Sendable (Element) throws -> Key
+    typealias EqualityComparer = @Sendable (Key, Key) throws -> Bool
     
     private let source: Observable<Element>
     fileprivate let selector: KeySelector
diff --git a/RxSwift/Observables/Do.swift b/RxSwift/Observables/Do.swift
index 3c8c68b3d..0069c0dd7 100644
--- a/RxSwift/Observables/Do.swift
+++ b/RxSwift/Observables/Do.swift
@@ -23,7 +23,7 @@ extension ObservableType {
      - parameter onDispose: Action to invoke after subscription to source observable has been disposed for any reason. It can be either because sequence terminates for some reason or observer subscription being disposed.
      - returns: The source sequence with the side-effecting behavior applied.
      */
-    public func `do`(onNext: ((Element) throws -> Void)? = nil, afterNext: ((Element) throws -> Void)? = nil, onError: ((Swift.Error) throws -> Void)? = nil, afterError: ((Swift.Error) throws -> Void)? = nil, onCompleted: (() throws -> Void)? = nil, afterCompleted: (() throws -> Void)? = nil, onSubscribe: (() -> Void)? = nil, onSubscribed: (() -> Void)? = nil, onDispose: (() -> Void)? = nil)
+    public func `do`(onNext: (@Sendable (Element) throws -> Void)? = nil, afterNext: (@Sendable (Element) throws -> Void)? = nil, onError: (@Sendable (Swift.Error) throws -> Void)? = nil, afterError: (@Sendable (Swift.Error) throws -> Void)? = nil, onCompleted: (@Sendable () throws -> Void)? = nil, afterCompleted: (@Sendable () throws -> Void)? = nil, onSubscribe: (@Sendable () -> Void)? = nil, onSubscribed: (@Sendable () -> Void)? = nil, onDispose: (@Sendable () -> Void)? = nil)
         -> Observable<Element> {
             return Do(source: self.asObservable(), eventHandler: { e in
                 switch e {
@@ -47,10 +47,10 @@ extension ObservableType {
     }
 }
 
-final private class DoSink<Observer: ObserverType>: Sink<Observer>, ObserverType {
+final private class DoSink<Observer: ObserverType>: Sink<Observer>, ObserverType, @unchecked Sendable {
     typealias Element = Observer.Element 
-    typealias EventHandler = (Event<Element>) throws -> Void
-    typealias AfterEventHandler = (Event<Element>) throws -> Void
+    typealias EventHandler = @Sendable (Event<Element>) throws -> Void
+    typealias AfterEventHandler = @Sendable (Event<Element>) throws -> Void
     
     private let eventHandler: EventHandler
     private let afterEventHandler: AfterEventHandler
@@ -77,18 +77,18 @@ final private class DoSink<Observer: ObserverType>: Sink<Observer>, ObserverType
     }
 }
 
-final private class Do<Element>: Producer<Element> {
-    typealias EventHandler = (Event<Element>) throws -> Void
-    typealias AfterEventHandler = (Event<Element>) throws -> Void
+final private class Do<Element>: Producer<Element>, @unchecked Sendable {
+    typealias EventHandler = @Sendable (Event<Element>) throws -> Void
+    typealias AfterEventHandler = @Sendable (Event<Element>) throws -> Void
     
     private let source: Observable<Element>
     private let eventHandler: EventHandler
     private let afterEventHandler: AfterEventHandler
-    private let onSubscribe: (() -> Void)?
-    private let onSubscribed: (() -> Void)?
-    private let onDispose: (() -> Void)?
+    private let onSubscribe: (@Sendable () -> Void)?
+    private let onSubscribed: (@Sendable () -> Void)?
+    private let onDispose: (@Sendable () -> Void)?
     
-    init(source: Observable<Element>, eventHandler: @escaping EventHandler, afterEventHandler: @escaping AfterEventHandler, onSubscribe: (() -> Void)?, onSubscribed: (() -> Void)?, onDispose: (() -> Void)?) {
+    init(source: Observable<Element>, eventHandler: @escaping EventHandler, afterEventHandler: @escaping AfterEventHandler, onSubscribe: (@Sendable () -> Void)?, onSubscribed: (@Sendable () -> Void)?, onDispose: (@Sendable () -> Void)?) {
         self.source = source
         self.eventHandler = eventHandler
         self.afterEventHandler = afterEventHandler
diff --git a/RxSwift/Observables/ElementAt.swift b/RxSwift/Observables/ElementAt.swift
index 3f09c7087..4fd6330b8 100644
--- a/RxSwift/Observables/ElementAt.swift
+++ b/RxSwift/Observables/ElementAt.swift
@@ -35,7 +35,7 @@ extension ObservableType {
     }
 }
 
-final private class ElementAtSink<Observer: ObserverType>: Sink<Observer>, ObserverType {
+final private class ElementAtSink<Observer: ObserverType>: Sink<Observer>, ObserverType, @unchecked Sendable {
     typealias SourceType = Observer.Element
     typealias Parent = ElementAt<SourceType>
     
@@ -82,7 +82,7 @@ final private class ElementAtSink<Observer: ObserverType>: Sink<Observer>, Obser
     }
 }
 
-final private class ElementAt<SourceType>: Producer<SourceType> {
+final private class ElementAt<SourceType>: Producer<SourceType>, @unchecked Sendable {
     let source: Observable<SourceType>
     let throwOnEmpty: Bool
     let index: Int
diff --git a/RxSwift/Observables/Empty.swift b/RxSwift/Observables/Empty.swift
index 9ca596594..150be905f 100644
--- a/RxSwift/Observables/Empty.swift
+++ b/RxSwift/Observables/Empty.swift
@@ -19,7 +19,7 @@ extension ObservableType {
     }
 }
 
-final private class EmptyProducer<Element>: Producer<Element> {
+final private class EmptyProducer<Element>: Producer<Element>, @unchecked Sendable {
     override func subscribe<Observer: ObserverType>(_ observer: Observer) -> Disposable where Observer.Element == Element {
         observer.on(.completed)
         return Disposables.create()
diff --git a/RxSwift/Observables/Enumerated.swift b/RxSwift/Observables/Enumerated.swift
index ef8a0ff02..ded154f78 100644
--- a/RxSwift/Observables/Enumerated.swift
+++ b/RxSwift/Observables/Enumerated.swift
@@ -21,7 +21,7 @@ extension ObservableType {
     }
 }
 
-final private class EnumeratedSink<Element, Observer: ObserverType>: Sink<Observer>, ObserverType where Observer.Element == (index: Int, element: Element) {
+final private class EnumeratedSink<Element, Observer: ObserverType>: Sink<Observer>, ObserverType, @unchecked Sendable where Observer.Element == (index: Int, element: Element) {
     var index = 0
     
     func on(_ event: Event<Element>) {
@@ -46,7 +46,7 @@ final private class EnumeratedSink<Element, Observer: ObserverType>: Sink<Observ
     }
 }
 
-final private class Enumerated<Element>: Producer<(index: Int, element: Element)> {
+final private class Enumerated<Element>: Producer<(index: Int, element: Element)>, @unchecked Sendable {
     private let source: Observable<Element>
 
     init(source: Observable<Element>) {
diff --git a/RxSwift/Observables/Error.swift b/RxSwift/Observables/Error.swift
index 2e722d670..b15fa1773 100644
--- a/RxSwift/Observables/Error.swift
+++ b/RxSwift/Observables/Error.swift
@@ -19,7 +19,7 @@ extension ObservableType {
     }
 }
 
-final private class ErrorProducer<Element>: Producer<Element> {
+final private class ErrorProducer<Element>: Producer<Element>, @unchecked Sendable {
     private let error: Swift.Error
     
     init(error: Swift.Error) {
diff --git a/RxSwift/Observables/Filter.swift b/RxSwift/Observables/Filter.swift
index 61d3ce793..06a0bce1f 100644
--- a/RxSwift/Observables/Filter.swift
+++ b/RxSwift/Observables/Filter.swift
@@ -16,7 +16,7 @@ extension ObservableType {
      - parameter predicate: A function to test each source element for a condition.
      - returns: An observable sequence that contains elements from the input sequence that satisfy the condition.
      */
-    public func filter(_ predicate: @escaping (Element) throws -> Bool)
+    public func filter(_ predicate: @escaping @Sendable (Element) throws -> Bool)
         -> Observable<Element> {
         Filter(source: self.asObservable(), predicate: predicate)
     }
@@ -36,8 +36,8 @@ extension ObservableType {
     }
 }
 
-final private class FilterSink<Observer: ObserverType>: Sink<Observer>, ObserverType {
-    typealias Predicate = (Element) throws -> Bool
+final private class FilterSink<Observer: ObserverType>: Sink<Observer>, ObserverType, @unchecked Sendable {
+    typealias Predicate = @Sendable (Element) throws -> Bool
     typealias Element = Observer.Element
     
     private let predicate: Predicate
@@ -67,8 +67,8 @@ final private class FilterSink<Observer: ObserverType>: Sink<Observer>, Observer
     }
 }
 
-final private class Filter<Element>: Producer<Element> {
-    typealias Predicate = (Element) throws -> Bool
+final private class Filter<Element>: Producer<Element>, @unchecked Sendable {
+    typealias Predicate = @Sendable (Element) throws -> Bool
     
     private let source: Observable<Element>
     private let predicate: Predicate
diff --git a/RxSwift/Observables/First.swift b/RxSwift/Observables/First.swift
index 001411485..e3242c28d 100644
--- a/RxSwift/Observables/First.swift
+++ b/RxSwift/Observables/First.swift
@@ -6,7 +6,7 @@
 //  Copyright © 2017 Krunoslav Zaher. All rights reserved.
 //
 
-private final class FirstSink<Element, Observer: ObserverType> : Sink<Observer>, ObserverType where Observer.Element == Element? {
+private final class FirstSink<Element, Observer: ObserverType> : Sink<Observer>, ObserverType, @unchecked Sendable where Observer.Element == Element? {
     typealias Parent = First<Element>
 
     func on(_ event: Event<Element>) {
@@ -26,7 +26,7 @@ private final class FirstSink<Element, Observer: ObserverType> : Sink<Observer>,
     }
 }
 
-final class First<Element>: Producer<Element?> {
+final class First<Element>: Producer<Element?>, @unchecked Sendable {
     private let source: Observable<Element>
 
     init(source: Observable<Element>) {
diff --git a/RxSwift/Observables/Generate.swift b/RxSwift/Observables/Generate.swift
index 7b924b381..8f0f3be63 100644
--- a/RxSwift/Observables/Generate.swift
+++ b/RxSwift/Observables/Generate.swift
@@ -19,12 +19,12 @@ extension ObservableType {
      - parameter scheduler: Scheduler on which to run the generator loop.
      - returns: The generated sequence.
      */
-    public static func generate(initialState: Element, condition: @escaping (Element) throws -> Bool, scheduler: ImmediateSchedulerType = CurrentThreadScheduler.instance, iterate: @escaping (Element) throws -> Element) -> Observable<Element> {
+    public static func generate(initialState: Element, condition: @escaping @Sendable (Element) throws -> Bool, scheduler: ImmediateSchedulerType = CurrentThreadScheduler.instance, iterate: @escaping @Sendable (Element) throws -> Element) -> Observable<Element> {
         Generate(initialState: initialState, condition: condition, iterate: iterate, resultSelector: { $0 }, scheduler: scheduler)
     }
 }
 
-final private class GenerateSink<Sequence, Observer: ObserverType>: Sink<Observer> {
+final private class GenerateSink<Sequence, Observer: ObserverType>: Sink<Observer>, @unchecked Sendable {
     typealias Parent = Generate<Sequence, Observer.Element>
     
     private let parent: Parent
@@ -63,14 +63,14 @@ final private class GenerateSink<Sequence, Observer: ObserverType>: Sink<Observe
     }
 }
 
-final private class Generate<Sequence, Element>: Producer<Element> {
+final private class Generate<Sequence, Element>: Producer<Element>, @unchecked Sendable {
     fileprivate let initialState: Sequence
-    fileprivate let condition: (Sequence) throws -> Bool
-    fileprivate let iterate: (Sequence) throws -> Sequence
-    fileprivate let resultSelector: (Sequence) throws -> Element
+    fileprivate let condition: @Sendable (Sequence) throws -> Bool
+    fileprivate let iterate: @Sendable (Sequence) throws -> Sequence
+    fileprivate let resultSelector: @Sendable (Sequence) throws -> Element
     fileprivate let scheduler: ImmediateSchedulerType
     
-    init(initialState: Sequence, condition: @escaping (Sequence) throws -> Bool, iterate: @escaping (Sequence) throws -> Sequence, resultSelector: @escaping (Sequence) throws -> Element, scheduler: ImmediateSchedulerType) {
+    init(initialState: Sequence, condition: @escaping @Sendable (Sequence) throws -> Bool, iterate: @escaping @Sendable (Sequence) throws -> Sequence, resultSelector: @escaping @Sendable (Sequence) throws -> Element, scheduler: ImmediateSchedulerType) {
         self.initialState = initialState
         self.condition = condition
         self.iterate = iterate
diff --git a/RxSwift/Observables/GroupBy.swift b/RxSwift/Observables/GroupBy.swift
index 88cbda767..1dec82bd4 100644
--- a/RxSwift/Observables/GroupBy.swift
+++ b/RxSwift/Observables/GroupBy.swift
@@ -15,13 +15,13 @@ extension ObservableType {
      - parameter keySelector: A function to extract the key for each element.
      - returns: A sequence of observable groups, each of which corresponds to a unique key value, containing all elements that share that same key value.
      */
-    public func groupBy<Key: Hashable>(keySelector: @escaping (Element) throws -> Key)
+    public func groupBy<Key: Hashable>(keySelector: @escaping @Sendable (Element) throws -> Key)
         -> Observable<GroupedObservable<Key, Element>> {
         GroupBy(source: self.asObservable(), selector: keySelector)
     }
 }
 
-final private class GroupedObservableImpl<Element>: Observable<Element> {
+final private class GroupedObservableImpl<Element>: Observable<Element>, @unchecked Sendable {
     private var subject: PublishSubject<Element>
     private var refCount: RefCountDisposable
     
@@ -40,8 +40,9 @@ final private class GroupedObservableImpl<Element>: Observable<Element> {
 
 final private class GroupBySink<Key: Hashable, Element, Observer: ObserverType>
     : Sink<Observer>
-    , ObserverType where Observer.Element == GroupedObservable<Key, Element> {
-    typealias ResultType = Observer.Element 
+    , ObserverType
+    , @unchecked Sendable where Observer.Element == GroupedObservable<Key, Element> {
+    typealias ResultType = Observer.Element
     typealias Parent = GroupBy<Key, Element>
 
     private let parent: Parent
@@ -115,8 +116,8 @@ final private class GroupBySink<Key: Hashable, Element, Observer: ObserverType>
     }
 }
 
-final private class GroupBy<Key: Hashable, Element>: Producer<GroupedObservable<Key,Element>> {
-    typealias KeySelector = (Element) throws -> Key
+final private class GroupBy<Key: Hashable & Sendable, Element>: Producer<GroupedObservable<Key,Element>>, @unchecked Sendable {
+    typealias KeySelector = @Sendable (Element) throws -> Key
 
     fileprivate let source: Observable<Element>
     fileprivate let selector: KeySelector
diff --git a/RxSwift/Observables/Just.swift b/RxSwift/Observables/Just.swift
index 93490837f..6a1397e42 100644
--- a/RxSwift/Observables/Just.swift
+++ b/RxSwift/Observables/Just.swift
@@ -33,7 +33,7 @@ extension ObservableType {
     }
 }
 
-final private class JustScheduledSink<Observer: ObserverType>: Sink<Observer> {
+final private class JustScheduledSink<Observer: ObserverType>: Sink<Observer>, @unchecked Sendable {
     typealias Parent = JustScheduled<Observer.Element>
 
     private let parent: Parent
@@ -56,7 +56,7 @@ final private class JustScheduledSink<Observer: ObserverType>: Sink<Observer> {
     }
 }
 
-final private class JustScheduled<Element>: Producer<Element> {
+final private class JustScheduled<Element>: Producer<Element>, @unchecked Sendable {
     fileprivate let scheduler: ImmediateSchedulerType
     fileprivate let element: Element
 
@@ -72,7 +72,7 @@ final private class JustScheduled<Element>: Producer<Element> {
     }
 }
 
-final private class Just<Element>: Producer<Element> {
+final private class Just<Element>: Producer<Element>, @unchecked Sendable {
     private let element: Element
     
     init(element: Element) {
diff --git a/RxSwift/Observables/Map.swift b/RxSwift/Observables/Map.swift
index 693794431..c13e32e6b 100644
--- a/RxSwift/Observables/Map.swift
+++ b/RxSwift/Observables/Map.swift
@@ -17,14 +17,14 @@ extension ObservableType {
      - returns: An observable sequence whose elements are the result of invoking the transform function on each element of source.
 
      */
-    public func map<Result>(_ transform: @escaping (Element) throws -> Result)
+    public func map<Result>(_ transform: @escaping @Sendable (Element) throws -> Result)
         -> Observable<Result> {
         Map(source: self.asObservable(), transform: transform)
     }
 }
 
-final private class MapSink<SourceType, Observer: ObserverType>: Sink<Observer>, ObserverType {
-    typealias Transform = (SourceType) throws -> ResultType
+final private class MapSink<SourceType, Observer: ObserverType>: Sink<Observer>, ObserverType, @unchecked Sendable {
+    typealias Transform = @Sendable (SourceType) throws -> ResultType
 
     typealias ResultType = Observer.Element 
 
@@ -56,8 +56,8 @@ final private class MapSink<SourceType, Observer: ObserverType>: Sink<Observer>,
     }
 }
 
-final private class Map<SourceType, ResultType>: Producer<ResultType> {
-    typealias Transform = (SourceType) throws -> ResultType
+final private class Map<SourceType, ResultType>: Producer<ResultType>, @unchecked Sendable {
+    typealias Transform = @Sendable (SourceType) throws -> ResultType
 
     private let source: Observable<SourceType>
 
diff --git a/RxSwift/Observables/Materialize.swift b/RxSwift/Observables/Materialize.swift
index e2577be5d..4b1fd82bd 100644
--- a/RxSwift/Observables/Materialize.swift
+++ b/RxSwift/Observables/Materialize.swift
@@ -17,7 +17,7 @@ extension ObservableType {
     }
 }
 
-private final class MaterializeSink<Element, Observer: ObserverType>: Sink<Observer>, ObserverType where Observer.Element == Event<Element> {
+private final class MaterializeSink<Element, Observer: ObserverType>: Sink<Observer>, ObserverType, @unchecked Sendable where Observer.Element == Event<Element> {
 
     func on(_ event: Event<Element>) {
         self.forwardOn(.next(event))
@@ -28,7 +28,7 @@ private final class MaterializeSink<Element, Observer: ObserverType>: Sink<Obser
     }
 }
 
-final private class Materialize<T>: Producer<Event<T>> {
+final private class Materialize<T>: Producer<Event<T>>, @unchecked Sendable {
     private let source: Observable<T>
 
     init(source: Observable<T>) {
diff --git a/RxSwift/Observables/Merge.swift b/RxSwift/Observables/Merge.swift
index 51a646291..e5a91b3d5 100644
--- a/RxSwift/Observables/Merge.swift
+++ b/RxSwift/Observables/Merge.swift
@@ -16,7 +16,7 @@ extension ObservableType {
      - parameter selector: A transform function to apply to each element.
      - returns: An observable sequence whose elements are the result of invoking the one-to-many transform function on each element of the input sequence.
      */
-    public func flatMap<Source: ObservableConvertibleType>(_ selector: @escaping (Element) throws -> Source)
+    public func flatMap<Source: ObservableConvertibleType>(_ selector: @escaping @Sendable (Element) throws -> Source)
         -> Observable<Source.Element> {
             return FlatMap(source: self.asObservable(), selector: selector)
     }
@@ -34,7 +34,7 @@ extension ObservableType {
      - parameter selector: A transform function to apply to element that was observed while no observable is executing in parallel.
      - returns: An observable sequence whose elements are the result of invoking the one-to-many transform function on each element of the input sequence that was received while no other sequence was being calculated.
      */
-    public func flatMapFirst<Source: ObservableConvertibleType>(_ selector: @escaping (Element) throws -> Source)
+    public func flatMapFirst<Source: ObservableConvertibleType>(_ selector: @escaping @Sendable (Element) throws -> Source)
         -> Observable<Source.Element> {
             return FlatMapFirst(source: self.asObservable(), selector: selector)
     }
@@ -130,7 +130,7 @@ extension ObservableType {
      - returns: An observable sequence that contains the elements of each observed inner sequence, in sequential order.
      */
     
-    public func concatMap<Source: ObservableConvertibleType>(_ selector: @escaping (Element) throws -> Source)
+    public func concatMap<Source: ObservableConvertibleType>(_ selector: @escaping @Sendable (Element) throws -> Source)
         -> Observable<Source.Element> {
         return ConcatMap(source: self.asObservable(), selector: selector)
     }
@@ -139,7 +139,8 @@ extension ObservableType {
 private final class MergeLimitedSinkIter<SourceElement, SourceSequence: ObservableConvertibleType, Observer: ObserverType>
     : ObserverType
     , LockOwnerType
-    , SynchronizedOnType where SourceSequence.Element == Observer.Element {
+    , SynchronizedOnType
+    , @unchecked Sendable where SourceSequence.Element == Observer.Element {
     typealias Element = Observer.Element
     typealias DisposeKey = CompositeDisposable.DisposeKey
     typealias Parent = MergeLimitedSink<SourceElement, SourceSequence, Observer>
@@ -184,8 +185,8 @@ private final class MergeLimitedSinkIter<SourceElement, SourceSequence: Observab
     }
 }
 
-private final class ConcatMapSink<SourceElement, SourceSequence: ObservableConvertibleType, Observer: ObserverType>: MergeLimitedSink<SourceElement, SourceSequence, Observer> where Observer.Element == SourceSequence.Element {
-    typealias Selector = (SourceElement) throws -> SourceSequence
+private final class ConcatMapSink<SourceElement, SourceSequence: ObservableConvertibleType, Observer: ObserverType>: MergeLimitedSink<SourceElement, SourceSequence, Observer>, @unchecked Sendable where Observer.Element == SourceSequence.Element {
+    typealias Selector = @Sendable (SourceElement) throws -> SourceSequence
     
     private let selector: Selector
     
@@ -199,7 +200,7 @@ private final class ConcatMapSink<SourceElement, SourceSequence: ObservableConve
     }
 }
 
-private final class MergeLimitedBasicSink<SourceSequence: ObservableConvertibleType, Observer: ObserverType>: MergeLimitedSink<SourceSequence, SourceSequence, Observer> where Observer.Element == SourceSequence.Element {
+private final class MergeLimitedBasicSink<SourceSequence: ObservableConvertibleType, Observer: ObserverType>: MergeLimitedSink<SourceSequence, SourceSequence, Observer>, @unchecked Sendable where Observer.Element == SourceSequence.Element {
     
     override func performMap(_ element: SourceSequence) throws -> SourceSequence {
         element
@@ -208,7 +209,8 @@ private final class MergeLimitedBasicSink<SourceSequence: ObservableConvertibleT
 
 private class MergeLimitedSink<SourceElement, SourceSequence: ObservableConvertibleType, Observer: ObserverType>
     : Sink<Observer>
-    , ObserverType where Observer.Element == SourceSequence.Element {
+    , ObserverType
+    , @unchecked Sendable where Observer.Element == SourceSequence.Element {
     typealias QueueType = Queue<SourceSequence>
 
     let maxConcurrent: Int
@@ -312,7 +314,7 @@ private class MergeLimitedSink<SourceElement, SourceSequence: ObservableConverti
     }
 }
 
-final private class MergeLimited<SourceSequence: ObservableConvertibleType>: Producer<SourceSequence.Element> {
+final private class MergeLimited<SourceSequence: ObservableConvertibleType>: Producer<SourceSequence.Element>, @unchecked Sendable {
     private let source: Observable<SourceSequence>
     private let maxConcurrent: Int
     
@@ -330,7 +332,7 @@ final private class MergeLimited<SourceSequence: ObservableConvertibleType>: Pro
 
 // MARK: Merge
 
-private final class MergeBasicSink<Source: ObservableConvertibleType, Observer: ObserverType> : MergeSink<Source, Source, Observer> where Observer.Element == Source.Element {
+private final class MergeBasicSink<Source: ObservableConvertibleType, Observer: ObserverType> : MergeSink<Source, Source, Observer>, @unchecked Sendable where Observer.Element == Source.Element {
     override func performMap(_ element: Source) throws -> Source {
         element
     }
@@ -338,8 +340,8 @@ private final class MergeBasicSink<Source: ObservableConvertibleType, Observer:
 
 // MARK: flatMap
 
-private final class FlatMapSink<SourceElement, SourceSequence: ObservableConvertibleType, Observer: ObserverType> : MergeSink<SourceElement, SourceSequence, Observer> where Observer.Element == SourceSequence.Element {
-    typealias Selector = (SourceElement) throws -> SourceSequence
+private final class FlatMapSink<SourceElement, SourceSequence: ObservableConvertibleType, Observer: ObserverType> : MergeSink<SourceElement, SourceSequence, Observer>, @unchecked Sendable where Observer.Element == SourceSequence.Element {
+    typealias Selector = @Sendable (SourceElement) throws -> SourceSequence
 
     private let selector: Selector
 
@@ -355,8 +357,8 @@ private final class FlatMapSink<SourceElement, SourceSequence: ObservableConvert
 
 // MARK: FlatMapFirst
 
-private final class FlatMapFirstSink<SourceElement, SourceSequence: ObservableConvertibleType, Observer: ObserverType> : MergeSink<SourceElement, SourceSequence, Observer> where Observer.Element == SourceSequence.Element {
-    typealias Selector = (SourceElement) throws -> SourceSequence
+private final class FlatMapFirstSink<SourceElement, SourceSequence: ObservableConvertibleType, Observer: ObserverType> : MergeSink<SourceElement, SourceSequence, Observer>, @unchecked Sendable where Observer.Element == SourceSequence.Element {
+    typealias Selector = @Sendable (SourceElement) throws -> SourceSequence
 
     private let selector: Selector
 
@@ -374,7 +376,7 @@ private final class FlatMapFirstSink<SourceElement, SourceSequence: ObservableCo
     }
 }
 
-private final class MergeSinkIter<SourceElement, SourceSequence: ObservableConvertibleType, Observer: ObserverType> : ObserverType where Observer.Element == SourceSequence.Element {
+private final class MergeSinkIter<SourceElement, SourceSequence: ObservableConvertibleType, Observer: ObserverType> : ObserverType, @unchecked Sendable where Observer.Element == SourceSequence.Element {
     typealias Parent = MergeSink<SourceElement, SourceSequence, Observer>
     typealias DisposeKey = CompositeDisposable.DisposeKey
     typealias Element = Observer.Element
@@ -407,7 +409,8 @@ private final class MergeSinkIter<SourceElement, SourceSequence: ObservableConve
 
 private class MergeSink<SourceElement, SourceSequence: ObservableConvertibleType, Observer: ObserverType>
     : Sink<Observer>
-    , ObserverType where Observer.Element == SourceSequence.Element {
+    , ObserverType
+    , @unchecked Sendable where Observer.Element == SourceSequence.Element {
     typealias ResultType = Observer.Element
     typealias Element = SourceElement
 
@@ -515,8 +518,8 @@ private class MergeSink<SourceElement, SourceSequence: ObservableConvertibleType
 
 // MARK: Producers
 
-final private class FlatMap<SourceElement, SourceSequence: ObservableConvertibleType>: Producer<SourceSequence.Element> {
-    typealias Selector = (SourceElement) throws -> SourceSequence
+final private class FlatMap<SourceElement, SourceSequence: ObservableConvertibleType>: Producer<SourceSequence.Element>, @unchecked Sendable {
+    typealias Selector = @Sendable (SourceElement) throws -> SourceSequence
 
     private let source: Observable<SourceElement>
     
@@ -534,8 +537,8 @@ final private class FlatMap<SourceElement, SourceSequence: ObservableConvertible
     }
 }
 
-final private class FlatMapFirst<SourceElement, SourceSequence: ObservableConvertibleType>: Producer<SourceSequence.Element> {
-    typealias Selector = (SourceElement) throws -> SourceSequence
+final private class FlatMapFirst<SourceElement, SourceSequence: ObservableConvertibleType>: Producer<SourceSequence.Element>, @unchecked Sendable {
+    typealias Selector = @Sendable (SourceElement) throws -> SourceSequence
 
     private let source: Observable<SourceElement>
 
@@ -553,8 +556,8 @@ final private class FlatMapFirst<SourceElement, SourceSequence: ObservableConver
     }
 }
 
-final class ConcatMap<SourceElement, SourceSequence: ObservableConvertibleType>: Producer<SourceSequence.Element> {
-    typealias Selector = (SourceElement) throws -> SourceSequence
+final class ConcatMap<SourceElement, SourceSequence: ObservableConvertibleType>: Producer<SourceSequence.Element>, @unchecked Sendable {
+    typealias Selector = @Sendable (SourceElement) throws -> SourceSequence
     
     private let source: Observable<SourceElement>
     private let selector: Selector
@@ -571,7 +574,7 @@ final class ConcatMap<SourceElement, SourceSequence: ObservableConvertibleType>:
     }
 }
 
-final class Merge<SourceSequence: ObservableConvertibleType> : Producer<SourceSequence.Element> {
+final class Merge<SourceSequence: ObservableConvertibleType> : Producer<SourceSequence.Element>, @unchecked Sendable {
     private let source: Observable<SourceSequence>
 
     init(source: Observable<SourceSequence>) {
@@ -585,7 +588,7 @@ final class Merge<SourceSequence: ObservableConvertibleType> : Producer<SourceSe
     }
 }
 
-final private class MergeArray<Element>: Producer<Element> {
+final private class MergeArray<Element>: Producer<Element>, @unchecked Sendable {
     private let sources: [Observable<Element>]
 
     init(sources: [Observable<Element>]) {
diff --git a/RxSwift/Observables/Multicast.swift b/RxSwift/Observables/Multicast.swift
index 1ebcf0212..8ad07775e 100644
--- a/RxSwift/Observables/Multicast.swift
+++ b/RxSwift/Observables/Multicast.swift
@@ -11,7 +11,8 @@
  */
 public class ConnectableObservable<Element>
     : Observable<Element>
-    , ConnectableObservableType {
+    , ConnectableObservableType
+    , @unchecked Sendable {
 
     /**
      Connects the observable wrapper to its source. All subscribed observers will receive values from the underlying observable sequence as long as the connection is established.
@@ -38,7 +39,7 @@ extension ObservableType {
     - parameter selector: Selector function which can use the multicasted source sequence subject to the policies enforced by the created subject.
     - returns: An observable sequence that contains the elements of a sequence produced by multicasting the source sequence within a selector function.
     */
-    public func multicast<Subject: SubjectType, Result>(_ subjectSelector: @escaping () throws -> Subject, selector: @escaping (Observable<Subject.Element>) throws -> Observable<Result>)
+    public func multicast<Subject: SubjectType, Result>(_ subjectSelector: @escaping @Sendable () throws -> Subject, selector: @escaping @Sendable (Observable<Subject.Element>) throws -> Observable<Result>)
         -> Observable<Result> where Subject.Observer.Element == Element {
         return Multicast(
             source: self.asObservable(),
@@ -141,13 +142,13 @@ extension ObservableType {
      - parameter makeSubject: Factory function used to instantiate a subject for each connection.
      - returns: A connectable observable sequence that upon connection causes the source sequence to push results into the specified subject.
      */
-    public func multicast<Subject: SubjectType>(makeSubject: @escaping () -> Subject)
+    public func multicast<Subject: SubjectType>(makeSubject: @escaping @Sendable () -> Subject)
         -> ConnectableObservable<Subject.Element> where Subject.Observer.Element == Element {
         ConnectableObservableAdapter(source: self.asObservable(), makeSubject: makeSubject)
     }
 }
 
-final private class Connection<Subject: SubjectType>: ObserverType, Disposable {
+final private class Connection<Subject: SubjectType>: ObserverType, Disposable, @unchecked Sendable {
     typealias Element = Subject.Observer.Element
 
     private var lock: RecursiveLock
@@ -194,11 +195,12 @@ final private class Connection<Subject: SubjectType>: ObserverType, Disposable {
 }
 
 final private class ConnectableObservableAdapter<Subject: SubjectType>
-    : ConnectableObservable<Subject.Element> {
+    : ConnectableObservable<Subject.Element>
+    , @unchecked Sendable {
     typealias ConnectionType = Connection<Subject>
 
     private let source: Observable<Subject.Observer.Element>
-    private let makeSubject: () -> Subject
+    private let makeSubject: @Sendable () -> Subject
 
     fileprivate let lock = RecursiveLock()
     fileprivate var subject: Subject?
@@ -206,7 +208,7 @@ final private class ConnectableObservableAdapter<Subject: SubjectType>
     // state
     fileprivate var connection: ConnectionType?
 
-    init(source: Observable<Subject.Observer.Element>, makeSubject: @escaping () -> Subject) {
+    init(source: Observable<Subject.Observer.Element>, makeSubject: @escaping @Sendable () -> Subject) {
         self.source = source
         self.makeSubject = makeSubject
         self.subject = nil
@@ -245,8 +247,9 @@ final private class ConnectableObservableAdapter<Subject: SubjectType>
 
 final private class RefCountSink<ConnectableSource: ConnectableObservableType, Observer: ObserverType>
     : Sink<Observer>
-    , ObserverType where ConnectableSource.Element == Observer.Element {
-    typealias Element = Observer.Element 
+    , ObserverType
+    , @unchecked Sendable where ConnectableSource.Element == Observer.Element {
+    typealias Element = Observer.Element
     typealias Parent = RefCount<ConnectableSource>
 
     private let parent: Parent
@@ -320,7 +323,7 @@ final private class RefCountSink<ConnectableSource: ConnectableObservableType, O
     }
 }
 
-final private class RefCount<ConnectableSource: ConnectableObservableType>: Producer<ConnectableSource.Element> {
+final private class RefCount<ConnectableSource: ConnectableObservableType>: Producer<ConnectableSource.Element>, @unchecked Sendable {
     fileprivate let lock = RecursiveLock()
 
     // state
@@ -342,8 +345,8 @@ final private class RefCount<ConnectableSource: ConnectableObservableType>: Prod
     }
 }
 
-final private class MulticastSink<Subject: SubjectType, Observer: ObserverType>: Sink<Observer>, ObserverType {
-    typealias Element = Observer.Element 
+final private class MulticastSink<Subject: SubjectType, Observer: ObserverType>: Sink<Observer>, ObserverType, @unchecked Sendable {
+    typealias Element = Observer.Element
     typealias ResultType = Element
     typealias MutlicastType = Multicast<Subject, Observer.Element>
 
@@ -383,9 +386,9 @@ final private class MulticastSink<Subject: SubjectType, Observer: ObserverType>:
     }
 }
 
-final private class Multicast<Subject: SubjectType, Result>: Producer<Result> {
-    typealias SubjectSelectorType = () throws -> Subject
-    typealias SelectorType = (Observable<Subject.Element>) throws -> Observable<Result>
+final private class Multicast<Subject: SubjectType, Result>: Producer<Result>, @unchecked Sendable {
+    typealias SubjectSelectorType = @Sendable () throws -> Subject
+    typealias SelectorType = @Sendable (Observable<Subject.Element>) throws -> Observable<Result>
 
     fileprivate let source: Observable<Subject.Observer.Element>
     fileprivate let subjectSelector: SubjectSelectorType
diff --git a/RxSwift/Observables/Never.swift b/RxSwift/Observables/Never.swift
index 7b456eed9..f700c476a 100644
--- a/RxSwift/Observables/Never.swift
+++ b/RxSwift/Observables/Never.swift
@@ -20,7 +20,7 @@ extension ObservableType {
     }
 }
 
-final private class NeverProducer<Element>: Producer<Element> {
+final private class NeverProducer<Element>: Producer<Element>, @unchecked Sendable {
     override func subscribe<Observer: ObserverType>(_ observer: Observer) -> Disposable where Observer.Element == Element {
         Disposables.create()
     }
diff --git a/RxSwift/Observables/ObserveOn.swift b/RxSwift/Observables/ObserveOn.swift
index 6b8689e1e..a8e976440 100644
--- a/RxSwift/Observables/ObserveOn.swift
+++ b/RxSwift/Observables/ObserveOn.swift
@@ -46,7 +46,7 @@ extension ObservableType {
     }
 }
 
-final private class ObserveOn<Element>: Producer<Element> {
+final private class ObserveOn<Element>: Producer<Element>, @unchecked Sendable {
     let scheduler: ImmediateSchedulerType
     let source: Observable<Element>
 
@@ -79,17 +79,17 @@ enum ObserveOnState : Int32 {
     case running = 1
 }
 
-final private class ObserveOnSink<Observer: ObserverType>: ObserverBase<Observer.Element> {
+final private class ObserveOnSink<Observer: ObserverType>: ObserverBase<Observer.Element>, @unchecked Sendable {
     typealias Element = Observer.Element 
 
     let scheduler: ImmediateSchedulerType
 
-    var lock = SpinLock()
+    let lock = SpinLock()
     let observer: Observer
 
     // state
-    var state = ObserveOnState.stopped
-    var queue = Queue<Event<Element>>(capacity: 10)
+    nonisolated(unsafe) var state = ObserveOnState.stopped
+    nonisolated(unsafe) var queue = Queue<Event<Element>>(capacity: 10)
 
     let scheduleDisposable = SerialDisposable()
     let cancel: Cancelable
@@ -118,6 +118,7 @@ final private class ObserveOnSink<Observer: ObserverType>: ObserverBase<Observer
         }
     }
 
+    @Sendable
     func run(_ state: (), _ recurse: (()) -> Void) {
         let (nextEvent, observer) = self.lock.performLocked { () -> (Event<Element>?, Observer) in
             if !self.queue.isEmpty {
@@ -176,13 +177,13 @@ final private class ObserveOnSink<Observer: ObserverType>: ObserverBase<Observer
     }
 #endif
 
-final private class ObserveOnSerialDispatchQueueSink<Observer: ObserverType>: ObserverBase<Observer.Element> {
+final private class ObserveOnSerialDispatchQueueSink<Observer: ObserverType>: ObserverBase<Observer.Element>, @unchecked Sendable {
     let scheduler: SerialDispatchQueueScheduler
     let observer: Observer
 
     let cancel: Cancelable
 
-    var cachedScheduleLambda: (((sink: ObserveOnSerialDispatchQueueSink<Observer>, event: Event<Element>)) -> Disposable)!
+    nonisolated(unsafe) var cachedScheduleLambda: (@Sendable ((sink: ObserveOnSerialDispatchQueueSink<Observer>, event: Event<Element>)) -> Disposable)!
 
     init(scheduler: SerialDispatchQueueScheduler, observer: Observer, cancel: Cancelable) {
         self.scheduler = scheduler
@@ -190,7 +191,7 @@ final private class ObserveOnSerialDispatchQueueSink<Observer: ObserverType>: Ob
         self.cancel = cancel
         super.init()
 
-        self.cachedScheduleLambda = { pair in
+        self.cachedScheduleLambda = { @Sendable pair in
             guard !cancel.isDisposed else { return Disposables.create() }
 
             pair.sink.observer.on(pair.event)
@@ -214,7 +215,7 @@ final private class ObserveOnSerialDispatchQueueSink<Observer: ObserverType>: Ob
     }
 }
 
-final private class ObserveOnSerialDispatchQueue<Element>: Producer<Element> {
+final private class ObserveOnSerialDispatchQueue<Element>: Producer<Element>, @unchecked Sendable {
     let scheduler: SerialDispatchQueueScheduler
     let source: Observable<Element>
 
diff --git a/RxSwift/Observables/Optional.swift b/RxSwift/Observables/Optional.swift
index 64f8f1fdd..a12e34cff 100644
--- a/RxSwift/Observables/Optional.swift
+++ b/RxSwift/Observables/Optional.swift
@@ -33,7 +33,7 @@ extension ObservableType {
     }
 }
 
-final private class ObservableOptionalScheduledSink<Observer: ObserverType>: Sink<Observer> {
+final private class ObservableOptionalScheduledSink<Observer: ObserverType>: Sink<Observer>, @unchecked Sendable {
     typealias Element = Observer.Element 
     typealias Parent = ObservableOptionalScheduled<Element>
 
@@ -62,7 +62,7 @@ final private class ObservableOptionalScheduledSink<Observer: ObserverType>: Sin
     }
 }
 
-final private class ObservableOptionalScheduled<Element>: Producer<Element> {
+final private class ObservableOptionalScheduled<Element>: Producer<Element>, @unchecked Sendable {
     fileprivate let optional: Element?
     fileprivate let scheduler: ImmediateSchedulerType
 
@@ -78,7 +78,7 @@ final private class ObservableOptionalScheduled<Element>: Producer<Element> {
     }
 }
 
-final private class ObservableOptional<Element>: Producer<Element> {
+final private class ObservableOptional<Element>: Producer<Element>, @unchecked Sendable {
     private let optional: Element?
     
     init(optional: Element?) {
diff --git a/RxSwift/Observables/Producer.swift b/RxSwift/Observables/Producer.swift
index e611930a5..0286ef952 100644
--- a/RxSwift/Observables/Producer.swift
+++ b/RxSwift/Observables/Producer.swift
@@ -6,7 +6,7 @@
 //  Copyright © 2015 Krunoslav Zaher. All rights reserved.
 //
 
-class Producer<Element>: Observable<Element> {
+class Producer<Element>: Observable<Element>, @unchecked Sendable {
     override init() {
         super.init()
     }
@@ -36,7 +36,7 @@ class Producer<Element>: Observable<Element> {
     }
 }
 
-private final class SinkDisposer: Cancelable {
+private final class SinkDisposer: Cancelable, @unchecked Sendable {
     private enum DisposeState: Int32 {
         case disposed = 1
         case sinkAndSubscriptionSet = 2
diff --git a/RxSwift/Observables/Range.swift b/RxSwift/Observables/Range.swift
index 245353249..f736ace1f 100644
--- a/RxSwift/Observables/Range.swift
+++ b/RxSwift/Observables/Range.swift
@@ -22,7 +22,7 @@ extension ObservableType where Element: RxAbstractInteger {
     }
 }
 
-final private class RangeProducer<Element: RxAbstractInteger>: Producer<Element> {
+final private class RangeProducer<Element: RxAbstractInteger>: Producer<Element>, @unchecked Sendable {
     fileprivate let start: Element
     fileprivate let count: Element
     fileprivate let scheduler: ImmediateSchedulerType
@@ -48,7 +48,7 @@ final private class RangeProducer<Element: RxAbstractInteger>: Producer<Element>
     }
 }
 
-final private class RangeSink<Observer: ObserverType>: Sink<Observer> where Observer.Element: RxAbstractInteger {
+final private class RangeSink<Observer: ObserverType>: Sink<Observer>, @unchecked Sendable where Observer.Element: RxAbstractInteger {
     typealias Parent = RangeProducer<Observer.Element>
     
     private let parent: Parent
diff --git a/RxSwift/Observables/Reduce.swift b/RxSwift/Observables/Reduce.swift
index d5fab3478..016c0309f 100644
--- a/RxSwift/Observables/Reduce.swift
+++ b/RxSwift/Observables/Reduce.swift
@@ -20,7 +20,7 @@ extension ObservableType {
     - parameter mapResult: A function to transform the final accumulator value into the result value.
     - returns: An observable sequence containing a single element with the final accumulator value.
     */
-    public func reduce<A, Result>(_ seed: A, accumulator: @escaping (A, Element) throws -> A, mapResult: @escaping (A) throws -> Result)
+    public func reduce<A, Result>(_ seed: A, accumulator: @escaping @Sendable (A, Element) throws -> A, mapResult: @escaping @Sendable (A) throws -> Result)
         -> Observable<Result> {
         Reduce(source: self.asObservable(), seed: seed, accumulator: accumulator, mapResult: mapResult)
     }
@@ -36,13 +36,13 @@ extension ObservableType {
     - parameter accumulator: A accumulator function to be invoked on each element.
     - returns: An observable sequence containing a single element with the final accumulator value.
     */
-    public func reduce<A>(_ seed: A, accumulator: @escaping (A, Element) throws -> A)
+    public func reduce<A>(_ seed: A, accumulator: @escaping @Sendable (A, Element) throws -> A)
         -> Observable<A> {
         Reduce(source: self.asObservable(), seed: seed, accumulator: accumulator, mapResult: { $0 })
     }
 }
 
-final private class ReduceSink<SourceType, AccumulateType, Observer: ObserverType>: Sink<Observer>, ObserverType {
+final private class ReduceSink<SourceType, AccumulateType, Observer: ObserverType>: Sink<Observer>, ObserverType, @unchecked Sendable {
     typealias ResultType = Observer.Element 
     typealias Parent = Reduce<SourceType, AccumulateType, ResultType>
     
@@ -84,9 +84,9 @@ final private class ReduceSink<SourceType, AccumulateType, Observer: ObserverTyp
     }
 }
 
-final private class Reduce<SourceType, AccumulateType, ResultType>: Producer<ResultType> {
-    typealias AccumulatorType = (AccumulateType, SourceType) throws -> AccumulateType
-    typealias ResultSelectorType = (AccumulateType) throws -> ResultType
+final private class Reduce<SourceType, AccumulateType, ResultType>: Producer<ResultType>, @unchecked Sendable {
+    typealias AccumulatorType = @Sendable (AccumulateType, SourceType) throws -> AccumulateType
+    typealias ResultSelectorType = @Sendable (AccumulateType) throws -> ResultType
     
     private let source: Observable<SourceType>
     fileprivate let seed: AccumulateType
diff --git a/RxSwift/Observables/Repeat.swift b/RxSwift/Observables/Repeat.swift
index 69a3ba02e..272c739a5 100644
--- a/RxSwift/Observables/Repeat.swift
+++ b/RxSwift/Observables/Repeat.swift
@@ -21,7 +21,7 @@ extension ObservableType {
     }
 }
 
-final private class RepeatElement<Element>: Producer<Element> {
+final private class RepeatElement<Element>: Producer<Element>, @unchecked Sendable {
     fileprivate let element: Element
     fileprivate let scheduler: ImmediateSchedulerType
     
@@ -38,7 +38,7 @@ final private class RepeatElement<Element>: Producer<Element> {
     }
 }
 
-final private class RepeatElementSink<Observer: ObserverType>: Sink<Observer> {
+final private class RepeatElementSink<Observer: ObserverType>: Sink<Observer>, @unchecked Sendable {
     typealias Parent = RepeatElement<Observer.Element>
     
     private let parent: Parent
diff --git a/RxSwift/Observables/RetryWhen.swift b/RxSwift/Observables/RetryWhen.swift
index e05c1599e..4e0ef284d 100644
--- a/RxSwift/Observables/RetryWhen.swift
+++ b/RxSwift/Observables/RetryWhen.swift
@@ -16,7 +16,7 @@ extension ObservableType {
      - parameter notificationHandler: A handler that is passed an observable sequence of errors raised by the source observable and returns and observable that either continues, completes or errors. This behavior is then applied to the source observable.
      - returns: An observable sequence producing the elements of the given sequence repeatedly until it terminates successfully or is notified to error or complete.
      */
-    public func retry<TriggerObservable: ObservableType, Error: Swift.Error>(when notificationHandler: @escaping (Observable<Error>) -> TriggerObservable)
+    public func retry<TriggerObservable: ObservableType, Error: Swift.Error>(when notificationHandler: @escaping @Sendable (Observable<Error>) -> TriggerObservable)
         -> Observable<Element> {
         RetryWhenSequence(sources: InfiniteSequence(repeatedValue: self.asObservable()), notificationHandler: notificationHandler)
     }
@@ -31,7 +31,7 @@ extension ObservableType {
      - returns: An observable sequence producing the elements of the given sequence repeatedly until it terminates successfully or is notified to error or complete.
      */
     @available(*, deprecated, renamed: "retry(when:)")
-    public func retryWhen<TriggerObservable: ObservableType, Error: Swift.Error>(_ notificationHandler: @escaping (Observable<Error>) -> TriggerObservable)
+    public func retryWhen<TriggerObservable: ObservableType, Error: Swift.Error>(_ notificationHandler: @escaping @Sendable (Observable<Error>) -> TriggerObservable)
         -> Observable<Element> {
         retry(when: notificationHandler)
     }
@@ -45,7 +45,7 @@ extension ObservableType {
      - parameter notificationHandler: A handler that is passed an observable sequence of errors raised by the source observable and returns and observable that either continues, completes or errors. This behavior is then applied to the source observable.
      - returns: An observable sequence producing the elements of the given sequence repeatedly until it terminates successfully or is notified to error or complete.
      */
-    public func retry<TriggerObservable: ObservableType>(when notificationHandler: @escaping (Observable<Swift.Error>) -> TriggerObservable)
+    public func retry<TriggerObservable: ObservableType>(when notificationHandler: @escaping @Sendable (Observable<Swift.Error>) -> TriggerObservable)
         -> Observable<Element> {
         RetryWhenSequence(sources: InfiniteSequence(repeatedValue: self.asObservable()), notificationHandler: notificationHandler)
     }
@@ -60,7 +60,7 @@ extension ObservableType {
      - returns: An observable sequence producing the elements of the given sequence repeatedly until it terminates successfully or is notified to error or complete.
      */
     @available(*, deprecated, renamed: "retry(when:)")
-    public func retryWhen<TriggerObservable: ObservableType>(_ notificationHandler: @escaping (Observable<Swift.Error>) -> TriggerObservable)
+    public func retryWhen<TriggerObservable: ObservableType>(_ notificationHandler: @escaping @Sendable (Observable<Swift.Error>) -> TriggerObservable)
         -> Observable<Element> {
         RetryWhenSequence(sources: InfiniteSequence(repeatedValue: self.asObservable()), notificationHandler: notificationHandler)
     }
@@ -140,8 +140,9 @@ final private class RetryWhenSequenceSinkIter<Sequence: Swift.Sequence, Observer
 }
 
 final private class RetryWhenSequenceSink<Sequence: Swift.Sequence, Observer: ObserverType, TriggerObservable: ObservableType, Error>
-    : TailRecursiveSink<Sequence, Observer> where Sequence.Element: ObservableType, Sequence.Element.Element == Observer.Element {
-    typealias Element = Observer.Element 
+    : TailRecursiveSink<Sequence, Observer>
+    , @unchecked Sendable where Sequence.Element: ObservableType, Sequence.Element.Element == Observer.Element {
+    typealias Element = Observer.Element
     typealias Parent = RetryWhenSequence<Sequence, TriggerObservable, Error>
     
     let lock = RecursiveLock()
@@ -192,13 +193,13 @@ final private class RetryWhenSequenceSink<Sequence: Swift.Sequence, Observer: Ob
     }
 }
 
-final private class RetryWhenSequence<Sequence: Swift.Sequence, TriggerObservable: ObservableType, Error>: Producer<Sequence.Element.Element> where Sequence.Element: ObservableType {
+final private class RetryWhenSequence<Sequence: Swift.Sequence, TriggerObservable: ObservableType, Error>: Producer<Sequence.Element.Element>, @unchecked Sendable where Sequence.Element: ObservableType {
     typealias Element = Sequence.Element.Element
     
     private let sources: Sequence
-    fileprivate let notificationHandler: (Observable<Error>) -> TriggerObservable
+    fileprivate let notificationHandler: @Sendable (Observable<Error>) -> TriggerObservable
     
-    init(sources: Sequence, notificationHandler: @escaping (Observable<Error>) -> TriggerObservable) {
+    init(sources: Sequence, notificationHandler: @escaping @Sendable (Observable<Error>) -> TriggerObservable) {
         self.sources = sources
         self.notificationHandler = notificationHandler
     }
diff --git a/RxSwift/Observables/Sample.swift b/RxSwift/Observables/Sample.swift
index 9301c9af7..3c8bb9b17 100644
--- a/RxSwift/Observables/Sample.swift
+++ b/RxSwift/Observables/Sample.swift
@@ -73,8 +73,9 @@ final private class SampleSequenceSink<Observer: ObserverType, SampleType>
     : Sink<Observer>
     , ObserverType
     , LockOwnerType
-    , SynchronizedOnType {
-    typealias Element = Observer.Element 
+    , SynchronizedOnType
+    , @unchecked Sendable {
+    typealias Element = Observer.Element
     typealias Parent = Sample<Element, SampleType>
     
     fileprivate let parent: Parent
@@ -120,7 +121,7 @@ final private class SampleSequenceSink<Observer: ObserverType, SampleType>
     
 }
 
-final private class Sample<Element, SampleType>: Producer<Element> {
+final private class Sample<Element, SampleType>: Producer<Element>, @unchecked Sendable {
     fileprivate let source: Observable<Element>
     fileprivate let sampler: Observable<SampleType>
     fileprivate let defaultValue: Element?
diff --git a/RxSwift/Observables/Scan.swift b/RxSwift/Observables/Scan.swift
index ecf69c80c..3aef6782c 100644
--- a/RxSwift/Observables/Scan.swift
+++ b/RxSwift/Observables/Scan.swift
@@ -19,7 +19,7 @@ extension ObservableType {
      - parameter accumulator: An accumulator function to be invoked on each element.
      - returns: An observable sequence containing the accumulated values.
      */
-    public func scan<A>(into seed: A, accumulator: @escaping (inout A, Element) throws -> Void)
+    public func scan<A>(into seed: A, accumulator: @escaping @Sendable (inout A, Element) throws -> Void)
         -> Observable<A> {
         Scan(source: self.asObservable(), seed: seed, accumulator: accumulator)
     }
@@ -35,7 +35,7 @@ extension ObservableType {
      - parameter accumulator: An accumulator function to be invoked on each element.
      - returns: An observable sequence containing the accumulated values.
      */
-    public func scan<A>(_ seed: A, accumulator: @escaping (A, Element) throws -> A)
+    public func scan<A>(_ seed: A, accumulator: @escaping @Sendable (A, Element) throws -> A)
         -> Observable<A> {
         return Scan(source: self.asObservable(), seed: seed) { acc, element in
             let currentAcc = acc
@@ -44,7 +44,7 @@ extension ObservableType {
     }
 }
 
-final private class ScanSink<Element, Observer: ObserverType>: Sink<Observer>, ObserverType {
+final private class ScanSink<Element, Observer: ObserverType>: Sink<Observer>, ObserverType, @unchecked Sendable {
     typealias Accumulate = Observer.Element 
     typealias Parent = Scan<Element, Accumulate>
 
@@ -79,8 +79,8 @@ final private class ScanSink<Element, Observer: ObserverType>: Sink<Observer>, O
     
 }
 
-final private class Scan<Element, Accumulate>: Producer<Accumulate> {
-    typealias Accumulator = (inout Accumulate, Element) throws -> Void
+final private class Scan<Element, Accumulate>: Producer<Accumulate>, @unchecked Sendable {
+    typealias Accumulator = @Sendable (inout Accumulate, Element) throws -> Void
     
     private let source: Observable<Element>
     fileprivate let seed: Accumulate
diff --git a/RxSwift/Observables/Sequence.swift b/RxSwift/Observables/Sequence.swift
index c6d10896e..29ca51943 100644
--- a/RxSwift/Observables/Sequence.swift
+++ b/RxSwift/Observables/Sequence.swift
@@ -47,7 +47,7 @@ extension ObservableType {
     }
 }
 
-final private class ObservableSequenceSink<Sequence: Swift.Sequence, Observer: ObserverType>: Sink<Observer> where Sequence.Element == Observer.Element {
+final private class ObservableSequenceSink<Sequence: Swift.Sequence, Observer: ObserverType>: Sink<Observer>, @unchecked Sendable where Sequence.Element == Observer.Element {
     typealias Parent = ObservableSequence<Sequence>
 
     private let parent: Parent
@@ -72,7 +72,7 @@ final private class ObservableSequenceSink<Sequence: Swift.Sequence, Observer: O
     }
 }
 
-final private class ObservableSequence<Sequence: Swift.Sequence>: Producer<Sequence.Element> {
+final private class ObservableSequence<Sequence: Swift.Sequence>: Producer<Sequence.Element>, @unchecked Sendable {
     fileprivate let elements: Sequence
     fileprivate let scheduler: ImmediateSchedulerType
 
diff --git a/RxSwift/Observables/ShareReplayScope.swift b/RxSwift/Observables/ShareReplayScope.swift
index 59d440dc3..68a2bb2e9 100644
--- a/RxSwift/Observables/ShareReplayScope.swift
+++ b/RxSwift/Observables/ShareReplayScope.swift
@@ -158,7 +158,8 @@ extension ObservableType {
 
 private final class ShareReplay1WhileConnectedConnection<Element>
     : ObserverType
-    , SynchronizedUnsubscribeType {
+    , SynchronizedUnsubscribeType
+    , @unchecked Sendable {
     typealias Observers = AnyObserver<Element>.s
     typealias DisposeKey = Observers.KeyType
 
@@ -255,7 +256,8 @@ private final class ShareReplay1WhileConnectedConnection<Element>
 
 // optimized version of share replay for most common case
 final private class ShareReplay1WhileConnected<Element>
-    : Observable<Element> {
+    : Observable<Element>
+    , @unchecked Sendable {
 
     fileprivate typealias Connection = ShareReplay1WhileConnectedConnection<Element>
 
@@ -304,7 +306,8 @@ final private class ShareReplay1WhileConnected<Element>
 
 private final class ShareWhileConnectedConnection<Element>
     : ObserverType
-    , SynchronizedUnsubscribeType {
+    , SynchronizedUnsubscribeType
+    , @unchecked Sendable {
     typealias Observers = AnyObserver<Element>.s
     typealias DisposeKey = Observers.KeyType
 
@@ -395,7 +398,8 @@ private final class ShareWhileConnectedConnection<Element>
 
 // optimized version of share replay for most common case
 final private class ShareWhileConnected<Element>
-    : Observable<Element> {
+    : Observable<Element>
+    , @unchecked Sendable {
 
     fileprivate typealias Connection = ShareWhileConnectedConnection<Element>
 
diff --git a/RxSwift/Observables/SingleAsync.swift b/RxSwift/Observables/SingleAsync.swift
index 04e221764..9dc23ae6b 100644
--- a/RxSwift/Observables/SingleAsync.swift
+++ b/RxSwift/Observables/SingleAsync.swift
@@ -30,13 +30,13 @@ extension ObservableType {
      - parameter predicate: A function to test each source element for a condition.
      - returns: An observable sequence that emits a single element or throws an exception if more (or none) of them are emitted.
      */
-    public func single(_ predicate: @escaping (Element) throws -> Bool)
+    public func single(_ predicate: @escaping @Sendable (Element) throws -> Bool)
         -> Observable<Element> {
         SingleAsync(source: self.asObservable(), predicate: predicate)
     }
 }
 
-private final class SingleAsyncSink<Observer: ObserverType> : Sink<Observer>, ObserverType {
+private final class SingleAsyncSink<Observer: ObserverType> : Sink<Observer>, ObserverType, @unchecked Sendable {
     typealias Element = Observer.Element
     typealias Parent = SingleAsync<Element>
     
@@ -85,8 +85,8 @@ private final class SingleAsyncSink<Observer: ObserverType> : Sink<Observer>, Ob
     }
 }
 
-final class SingleAsync<Element>: Producer<Element> {
-    typealias Predicate = (Element) throws -> Bool
+final class SingleAsync<Element>: Producer<Element>, @unchecked Sendable {
+    typealias Predicate = @Sendable (Element) throws -> Bool
     
     private let source: Observable<Element>
     fileprivate let predicate: Predicate?
diff --git a/RxSwift/Observables/Sink.swift b/RxSwift/Observables/Sink.swift
index ed4fec01e..f04eda75b 100644
--- a/RxSwift/Observables/Sink.swift
+++ b/RxSwift/Observables/Sink.swift
@@ -6,7 +6,7 @@
 //  Copyright © 2015 Krunoslav Zaher. All rights reserved.
 //
 
-class Sink<Observer: ObserverType>: Disposable {
+class Sink<Observer: ObserverType>: Disposable, @unchecked Sendable {
     fileprivate let observer: Observer
     fileprivate let cancel: Cancelable
     private let disposed = AtomicInt(0)
diff --git a/RxSwift/Observables/Skip.swift b/RxSwift/Observables/Skip.swift
index 1d7361e8a..15bb7dc98 100644
--- a/RxSwift/Observables/Skip.swift
+++ b/RxSwift/Observables/Skip.swift
@@ -43,7 +43,7 @@ extension ObservableType {
 
 // count version
 
-final private class SkipCountSink<Observer: ObserverType>: Sink<Observer>, ObserverType {
+final private class SkipCountSink<Observer: ObserverType>: Sink<Observer>, ObserverType, @unchecked Sendable {
     typealias Element = Observer.Element 
     typealias Parent = SkipCount<Element>
     
@@ -78,7 +78,7 @@ final private class SkipCountSink<Observer: ObserverType>: Sink<Observer>, Obser
     
 }
 
-final private class SkipCount<Element>: Producer<Element> {
+final private class SkipCount<Element>: Producer<Element>, @unchecked Sendable {
     let source: Observable<Element>
     let count: Int
     
@@ -97,7 +97,7 @@ final private class SkipCount<Element>: Producer<Element> {
 
 // time version
 
-final private class SkipTimeSink<Element, Observer: ObserverType>: Sink<Observer>, ObserverType where Observer.Element == Element {
+final private class SkipTimeSink<Element, Observer: ObserverType>: Sink<Observer>, ObserverType, @unchecked Sendable where Observer.Element == Element {
     typealias Parent = SkipTime<Element>
 
     let parent: Parent
@@ -141,7 +141,7 @@ final private class SkipTimeSink<Element, Observer: ObserverType>: Sink<Observer
     }
 }
 
-final private class SkipTime<Element>: Producer<Element> {
+final private class SkipTime<Element>: Producer<Element>, @unchecked Sendable {
     let source: Observable<Element>
     let duration: RxTimeInterval
     let scheduler: SchedulerType
diff --git a/RxSwift/Observables/SkipUntil.swift b/RxSwift/Observables/SkipUntil.swift
index c8fe19340..5a86f264d 100644
--- a/RxSwift/Observables/SkipUntil.swift
+++ b/RxSwift/Observables/SkipUntil.swift
@@ -87,8 +87,9 @@ final private class SkipUntilSink<Other, Observer: ObserverType>
     : Sink<Observer>
     , ObserverType
     , LockOwnerType
-    , SynchronizedOnType {
-    typealias Element = Observer.Element 
+    , SynchronizedOnType
+    , @unchecked Sendable {
+    typealias Element = Observer.Element
     typealias Parent = SkipUntil<Element, Other>
     
     let lock = RecursiveLock()
@@ -134,7 +135,7 @@ final private class SkipUntilSink<Other, Observer: ObserverType>
     }
 }
 
-final private class SkipUntil<Element, Other>: Producer<Element> {
+final private class SkipUntil<Element, Other>: Producer<Element>, @unchecked Sendable {
     
     fileprivate let source: Observable<Element>
     fileprivate let other: Observable<Other>
diff --git a/RxSwift/Observables/SkipWhile.swift b/RxSwift/Observables/SkipWhile.swift
index a62f88ddd..adb0b62d1 100644
--- a/RxSwift/Observables/SkipWhile.swift
+++ b/RxSwift/Observables/SkipWhile.swift
@@ -15,7 +15,7 @@ extension ObservableType {
      - parameter predicate: A function to test each element for a condition.
      - returns: An observable sequence that contains the elements from the input sequence starting at the first element in the linear series that does not pass the test specified by predicate.
      */
-    public func skip(while predicate: @escaping (Element) throws -> Bool) -> Observable<Element> {
+    public func skip(while predicate: @escaping @Sendable (Element) throws -> Bool) -> Observable<Element> {
         SkipWhile(source: self.asObservable(), predicate: predicate)
     }
 
@@ -28,12 +28,12 @@ extension ObservableType {
      - returns: An observable sequence that contains the elements from the input sequence starting at the first element in the linear series that does not pass the test specified by predicate.
      */
     @available(*, deprecated, renamed: "skip(while:)")
-    public func skipWhile(_ predicate: @escaping (Element) throws -> Bool) -> Observable<Element> {
+    public func skipWhile(_ predicate: @escaping @Sendable (Element) throws -> Bool) -> Observable<Element> {
         SkipWhile(source: self.asObservable(), predicate: predicate)
     }
 }
 
-final private class SkipWhileSink<Observer: ObserverType>: Sink<Observer>, ObserverType {
+final private class SkipWhileSink<Observer: ObserverType>: Sink<Observer>, ObserverType, @unchecked Sendable {
     typealias Element = Observer.Element 
     typealias Parent = SkipWhile<Element>
 
@@ -68,8 +68,8 @@ final private class SkipWhileSink<Observer: ObserverType>: Sink<Observer>, Obser
     }
 }
 
-final private class SkipWhile<Element>: Producer<Element> {
-    typealias Predicate = (Element) throws -> Bool
+final private class SkipWhile<Element>: Producer<Element>, @unchecked Sendable {
+    typealias Predicate = @Sendable (Element) throws -> Bool
 
     private let source: Observable<Element>
     fileprivate let predicate: Predicate
diff --git a/RxSwift/Observables/StartWith.swift b/RxSwift/Observables/StartWith.swift
index 13fb31d33..4758c1e40 100644
--- a/RxSwift/Observables/StartWith.swift
+++ b/RxSwift/Observables/StartWith.swift
@@ -22,7 +22,7 @@ extension ObservableType {
     }
 }
 
-final private class StartWith<Element>: Producer<Element> {
+final private class StartWith<Element>: Producer<Element>, @unchecked Sendable {
     let elements: [Element]
     let source: Observable<Element>
 
diff --git a/RxSwift/Observables/SubscribeOn.swift b/RxSwift/Observables/SubscribeOn.swift
index e8e41d9cf..9aba1146d 100644
--- a/RxSwift/Observables/SubscribeOn.swift
+++ b/RxSwift/Observables/SubscribeOn.swift
@@ -49,7 +49,7 @@ extension ObservableType {
     }
 }
 
-final private class SubscribeOnSink<Ob: ObservableType, Observer: ObserverType>: Sink<Observer>, ObserverType where Ob.Element == Observer.Element {
+final private class SubscribeOnSink<Ob: ObservableType, Observer: ObserverType>: Sink<Observer>, ObserverType, @unchecked Sendable where Ob.Element == Observer.Element {
     typealias Element = Observer.Element 
     typealias Parent = SubscribeOn<Ob>
     
@@ -86,7 +86,7 @@ final private class SubscribeOnSink<Ob: ObservableType, Observer: ObserverType>:
     }
 }
 
-final private class SubscribeOn<Ob: ObservableType>: Producer<Ob.Element> {
+final private class SubscribeOn<Ob: ObservableType>: Producer<Ob.Element>, @unchecked Sendable {
     let source: Ob
     let scheduler: ImmediateSchedulerType
     
diff --git a/RxSwift/Observables/Switch.swift b/RxSwift/Observables/Switch.swift
index 5aa60b97a..d0097a552 100644
--- a/RxSwift/Observables/Switch.swift
+++ b/RxSwift/Observables/Switch.swift
@@ -19,7 +19,7 @@ extension ObservableType {
      - returns: An observable sequence whose elements are the result of invoking the transform function on each element of source producing an
      Observable of Observable sequences and that at any point in time produces the elements of the most recent inner observable sequence that has been received.
      */
-    public func flatMapLatest<Source: ObservableConvertibleType>(_ selector: @escaping (Element) throws -> Source)
+    public func flatMapLatest<Source: ObservableConvertibleType>(_ selector: @escaping @Sendable (Element) throws -> Source)
         -> Observable<Source.Element> {
         return FlatMapLatest(source: self.asObservable(), selector: selector)
     }
@@ -36,7 +36,7 @@ extension ObservableType {
      - returns: An observable sequence whose elements are the result of invoking the transform function on each element of source producing an
      Observable of Observable sequences and that at any point in time produces the elements of the most recent inner observable sequence that has been received.
      */
-    public func flatMapLatest<Source: InfallibleType>(_ selector: @escaping (Element) throws -> Source)
+    public func flatMapLatest<Source: InfallibleType>(_ selector: @escaping @Sendable (Element) throws -> Source)
         -> Infallible<Source.Element> {
         return Infallible(flatMapLatest(selector))
     }
@@ -62,7 +62,8 @@ extension ObservableType where Element: ObservableConvertibleType {
 
 private class SwitchSink<SourceType, Source: ObservableConvertibleType, Observer: ObserverType>
     : Sink<Observer>
-    , ObserverType where Source.Element == Observer.Element {
+    , ObserverType
+    , @unchecked Sendable where Source.Element == Observer.Element {
     typealias Element = SourceType
 
     private let subscriptions: SingleAssignmentDisposable = SingleAssignmentDisposable()
@@ -190,7 +191,7 @@ final private class SwitchSinkIter<SourceType, Source: ObservableConvertibleType
 
 // MARK: Specializations
 
-final private class SwitchIdentitySink<Source: ObservableConvertibleType, Observer: ObserverType>: SwitchSink<Source, Source, Observer>
+final private class SwitchIdentitySink<Source: ObservableConvertibleType, Observer: ObserverType>: SwitchSink<Source, Source, Observer>, @unchecked Sendable
     where Observer.Element == Source.Element {
     override init(observer: Observer, cancel: Cancelable) {
         super.init(observer: observer, cancel: cancel)
@@ -201,8 +202,8 @@ final private class SwitchIdentitySink<Source: ObservableConvertibleType, Observ
     }
 }
 
-final private class MapSwitchSink<SourceType, Source: ObservableConvertibleType, Observer: ObserverType>: SwitchSink<SourceType, Source, Observer> where Observer.Element == Source.Element {
-    typealias Selector = (SourceType) throws -> Source
+final private class MapSwitchSink<SourceType, Source: ObservableConvertibleType, Observer: ObserverType>: SwitchSink<SourceType, Source, Observer>, @unchecked Sendable where Observer.Element == Source.Element {
+    typealias Selector = @Sendable (SourceType) throws -> Source
 
     private let selector: Selector
 
@@ -218,7 +219,7 @@ final private class MapSwitchSink<SourceType, Source: ObservableConvertibleType,
 
 // MARK: Producers
 
-final private class Switch<Source: ObservableConvertibleType>: Producer<Source.Element> {
+final private class Switch<Source: ObservableConvertibleType>: Producer<Source.Element>, @unchecked Sendable {
     private let source: Observable<Source>
     
     init(source: Observable<Source>) {
@@ -232,8 +233,8 @@ final private class Switch<Source: ObservableConvertibleType>: Producer<Source.E
     }
 }
 
-final private class FlatMapLatest<SourceType, Source: ObservableConvertibleType>: Producer<Source.Element> {
-    typealias Selector = (SourceType) throws -> Source
+final private class FlatMapLatest<SourceType, Source: ObservableConvertibleType>: Producer<Source.Element>, @unchecked Sendable {
+    typealias Selector = @Sendable (SourceType) throws -> Source
 
     private let source: Observable<SourceType>
     private let selector: Selector
diff --git a/RxSwift/Observables/SwitchIfEmpty.swift b/RxSwift/Observables/SwitchIfEmpty.swift
index 037bf6970..2500f5f6a 100644
--- a/RxSwift/Observables/SwitchIfEmpty.swift
+++ b/RxSwift/Observables/SwitchIfEmpty.swift
@@ -20,7 +20,7 @@ extension ObservableType {
     }
 }
 
-final private class SwitchIfEmpty<Element>: Producer<Element> {
+final private class SwitchIfEmpty<Element>: Producer<Element>, @unchecked Sendable {
     
     private let source: Observable<Element>
     private let ifEmpty: Observable<Element>
@@ -41,7 +41,8 @@ final private class SwitchIfEmpty<Element>: Producer<Element> {
 }
 
 final private class SwitchIfEmptySink<Observer: ObserverType>: Sink<Observer>
-    , ObserverType {
+    , ObserverType
+    , @unchecked Sendable {
     typealias Element = Observer.Element
     
     private let ifEmpty: Observable<Element>
diff --git a/RxSwift/Observables/Take.swift b/RxSwift/Observables/Take.swift
index acf3aaebd..784fd8973 100644
--- a/RxSwift/Observables/Take.swift
+++ b/RxSwift/Observables/Take.swift
@@ -62,7 +62,7 @@ extension ObservableType {
 
 // count version
 
-final private class TakeCountSink<Observer: ObserverType>: Sink<Observer>, ObserverType {
+final private class TakeCountSink<Observer: ObserverType>: Sink<Observer>, ObserverType, @unchecked Sendable {
     typealias Element = Observer.Element 
     typealias Parent = TakeCount<Element>
     
@@ -101,7 +101,7 @@ final private class TakeCountSink<Observer: ObserverType>: Sink<Observer>, Obser
     
 }
 
-final private class TakeCount<Element>: Producer<Element> {
+final private class TakeCount<Element>: Producer<Element>, @unchecked Sendable {
     private let source: Observable<Element>
     fileprivate let count: Int
     
@@ -126,7 +126,8 @@ final private class TakeTimeSink<Element, Observer: ObserverType>
     : Sink<Observer>
     , LockOwnerType
     , ObserverType
-    , SynchronizedOnType where Observer.Element == Element {
+    , SynchronizedOnType
+    , @unchecked Sendable where Observer.Element == Element {
     typealias Parent = TakeTime<Element>
 
     private let parent: Parent
@@ -174,7 +175,7 @@ final private class TakeTimeSink<Element, Observer: ObserverType>
     }
 }
 
-final private class TakeTime<Element>: Producer<Element> {
+final private class TakeTime<Element>: Producer<Element>, @unchecked Sendable {
     typealias TimeInterval = RxTimeInterval
     
     fileprivate let source: Observable<Element>
diff --git a/RxSwift/Observables/TakeLast.swift b/RxSwift/Observables/TakeLast.swift
index 91833872d..19dfc5d37 100644
--- a/RxSwift/Observables/TakeLast.swift
+++ b/RxSwift/Observables/TakeLast.swift
@@ -24,7 +24,7 @@ extension ObservableType {
     }
 }
 
-final private class TakeLastSink<Observer: ObserverType>: Sink<Observer>, ObserverType {
+final private class TakeLastSink<Observer: ObserverType>: Sink<Observer>, ObserverType, @unchecked Sendable {
     typealias Element = Observer.Element 
     typealias Parent = TakeLast<Element>
     
@@ -58,7 +58,7 @@ final private class TakeLastSink<Observer: ObserverType>: Sink<Observer>, Observ
     }
 }
 
-final private class TakeLast<Element>: Producer<Element> {
+final private class TakeLast<Element>: Producer<Element>, @unchecked Sendable {
     private let source: Observable<Element>
     fileprivate let count: Int
     
diff --git a/RxSwift/Observables/TakeWithPredicate.swift b/RxSwift/Observables/TakeWithPredicate.swift
index 6c28d19ba..bcf294ca8 100644
--- a/RxSwift/Observables/TakeWithPredicate.swift
+++ b/RxSwift/Observables/TakeWithPredicate.swift
@@ -30,7 +30,7 @@ extension ObservableType {
 
      - returns: An observable sequence that contains the elements from the input sequence that occur before the element at which the test passes.
      */
-    public func take(until predicate: @escaping (Element) throws -> Bool,
+    public func take(until predicate: @escaping @Sendable (Element) throws -> Bool,
                      behavior: TakeBehavior = .exclusive)
         -> Observable<Element> {
         TakeUntilPredicate(source: self.asObservable(),
@@ -46,7 +46,7 @@ extension ObservableType {
      - parameter predicate: A function to test each element for a condition.
      - returns: An observable sequence that contains the elements from the input sequence that occur before the element at which the test no longer passes.
      */
-    public func take(while predicate: @escaping (Element) throws -> Bool,
+    public func take(while predicate: @escaping @Sendable (Element) throws -> Bool,
                      behavior: TakeBehavior = .exclusive)
         -> Observable<Element> {
         take(until: { try !predicate($0) }, behavior: behavior)
@@ -77,7 +77,7 @@ extension ObservableType {
      */
     @available(*, deprecated, renamed: "take(until:behavior:)")
     public func takeUntil(_ behavior: TakeBehavior,
-                          predicate: @escaping (Element) throws -> Bool)
+                          predicate: @escaping @Sendable (Element) throws -> Bool)
         -> Observable<Element> {
         take(until: predicate, behavior: behavior)
     }
@@ -91,7 +91,7 @@ extension ObservableType {
      - returns: An observable sequence that contains the elements from the input sequence that occur before the element at which the test no longer passes.
      */
     @available(*, deprecated, renamed: "take(while:)")
-    public func takeWhile(_ predicate: @escaping (Element) throws -> Bool)
+    public func takeWhile(_ predicate: @escaping @Sendable (Element) throws -> Bool)
         -> Observable<Element> {
         take(until: { try !predicate($0) }, behavior: .exclusive)
     }
@@ -157,8 +157,9 @@ final private class TakeUntilSink<Other, Observer: ObserverType>
     : Sink<Observer>
     , LockOwnerType
     , ObserverType
-    , SynchronizedOnType {
-    typealias Element = Observer.Element 
+    , SynchronizedOnType
+    , @unchecked Sendable {
+    typealias Element = Observer.Element
     typealias Parent = TakeUntil<Element, Other>
     
     private let parent: Parent
@@ -198,7 +199,7 @@ final private class TakeUntilSink<Other, Observer: ObserverType>
     }
 }
 
-final private class TakeUntil<Element, Other>: Producer<Element> {
+final private class TakeUntil<Element, Other>: Producer<Element>, @unchecked Sendable {
     
     fileprivate let source: Observable<Element>
     fileprivate let other: Observable<Other>
@@ -217,7 +218,7 @@ final private class TakeUntil<Element, Other>: Producer<Element> {
 
 // MARK: - TakeUntil Predicate
 final private class TakeUntilPredicateSink<Observer: ObserverType>
-    : Sink<Observer>, ObserverType {
+    : Sink<Observer>, ObserverType, @unchecked Sendable {
     typealias Element = Observer.Element 
     typealias Parent = TakeUntilPredicate<Element>
 
@@ -262,8 +263,8 @@ final private class TakeUntilPredicateSink<Observer: ObserverType>
 
 }
 
-final private class TakeUntilPredicate<Element>: Producer<Element> {
-    typealias Predicate = (Element) throws -> Bool
+final private class TakeUntilPredicate<Element>: Producer<Element>, @unchecked Sendable {
+    typealias Predicate = @Sendable (Element) throws -> Bool
 
     private let source: Observable<Element>
     fileprivate let predicate: Predicate
diff --git a/RxSwift/Observables/Throttle.swift b/RxSwift/Observables/Throttle.swift
index 86152a837..fe9d6bc19 100644
--- a/RxSwift/Observables/Throttle.swift
+++ b/RxSwift/Observables/Throttle.swift
@@ -32,8 +32,9 @@ final private class ThrottleSink<Observer: ObserverType>
     : Sink<Observer>
     , ObserverType
     , LockOwnerType
-    , SynchronizedOnType {
-    typealias Element = Observer.Element 
+    , SynchronizedOnType
+    , @unchecked Sendable {
+    typealias Element = Observer.Element
     typealias ParentType = Throttle<Element>
     
     private let parent: ParentType
@@ -122,6 +123,7 @@ final private class ThrottleSink<Observer: ObserverType>
         self.lastSentTime = self.parent.scheduler.now
     }
     
+    @Sendable
     func propagate(_: Int) -> Disposable {
         self.lock.performLocked {
             if let lastUnsentElement = self.lastUnsentElement {
@@ -138,7 +140,7 @@ final private class ThrottleSink<Observer: ObserverType>
     }
 }
 
-final private class Throttle<Element>: Producer<Element> {
+final private class Throttle<Element>: Producer<Element>, @unchecked Sendable {
     fileprivate let source: Observable<Element>
     fileprivate let dueTime: RxTimeInterval
     fileprivate let latest: Bool
diff --git a/RxSwift/Observables/Timeout.swift b/RxSwift/Observables/Timeout.swift
index 7531eeeae..8d5f0f436 100644
--- a/RxSwift/Observables/Timeout.swift
+++ b/RxSwift/Observables/Timeout.swift
@@ -40,7 +40,7 @@ extension ObservableType {
     }
 }
 
-final private class TimeoutSink<Observer: ObserverType>: Sink<Observer>, LockOwnerType, ObserverType {
+final private class TimeoutSink<Observer: ObserverType>: Sink<Observer>, LockOwnerType, ObserverType, @unchecked Sendable {
     typealias Element = Observer.Element 
     typealias Parent = Timeout<Element>
     
@@ -132,7 +132,7 @@ final private class TimeoutSink<Observer: ObserverType>: Sink<Observer>, LockOwn
 }
 
 
-final private class Timeout<Element>: Producer<Element> {
+final private class Timeout<Element>: Producer<Element>, @unchecked Sendable {
     fileprivate let source: Observable<Element>
     fileprivate let dueTime: RxTimeInterval
     fileprivate let other: Observable<Element>
diff --git a/RxSwift/Observables/Timer.swift b/RxSwift/Observables/Timer.swift
index 30bbdf67d..4ebd051c5 100644
--- a/RxSwift/Observables/Timer.swift
+++ b/RxSwift/Observables/Timer.swift
@@ -49,7 +49,7 @@ extension ObservableType where Element: RxAbstractInteger {
 
 import Foundation
 
-final private class TimerSink<Observer: ObserverType> : Sink<Observer> where Observer.Element : RxAbstractInteger  {
+final private class TimerSink<Observer: ObserverType> : Sink<Observer>, @unchecked Sendable where Observer.Element : RxAbstractInteger  {
     typealias Parent = Timer<Observer.Element>
 
     private let parent: Parent
@@ -70,7 +70,7 @@ final private class TimerSink<Observer: ObserverType> : Sink<Observer> where Obs
     }
 }
 
-final private class TimerOneOffSink<Observer: ObserverType>: Sink<Observer> where Observer.Element: RxAbstractInteger {
+final private class TimerOneOffSink<Observer: ObserverType>: Sink<Observer>, @unchecked Sendable where Observer.Element: RxAbstractInteger {
     typealias Parent = Timer<Observer.Element>
 
     private let parent: Parent
@@ -91,7 +91,7 @@ final private class TimerOneOffSink<Observer: ObserverType>: Sink<Observer> wher
     }
 }
 
-final private class Timer<Element: RxAbstractInteger>: Producer<Element> {
+final private class Timer<Element: RxAbstractInteger>: Producer<Element>, @unchecked Sendable {
     fileprivate let scheduler: SchedulerType
     fileprivate let dueTime: RxTimeInterval
     fileprivate let period: RxTimeInterval?
diff --git a/RxSwift/Observables/ToArray.swift b/RxSwift/Observables/ToArray.swift
index 76c7370aa..0a2ba0011 100644
--- a/RxSwift/Observables/ToArray.swift
+++ b/RxSwift/Observables/ToArray.swift
@@ -22,7 +22,7 @@ extension ObservableType {
     }
 }
 
-final private class ToArraySink<SourceType, Observer: ObserverType>: Sink<Observer>, ObserverType where Observer.Element == [SourceType] {
+final private class ToArraySink<SourceType, Observer: ObserverType>: Sink<Observer>, ObserverType, @unchecked Sendable where Observer.Element == [SourceType] {
     typealias Parent = ToArray<SourceType>
     
     let parent: Parent
@@ -49,7 +49,7 @@ final private class ToArraySink<SourceType, Observer: ObserverType>: Sink<Observ
     }
 }
 
-final private class ToArray<SourceType>: Producer<[SourceType]> {
+final private class ToArray<SourceType>: Producer<[SourceType]>, @unchecked Sendable {
     let source: Observable<SourceType>
 
     init(source: Observable<SourceType>) {
diff --git a/RxSwift/Observables/Using.swift b/RxSwift/Observables/Using.swift
index ca48d2fb8..8ec59fe17 100644
--- a/RxSwift/Observables/Using.swift
+++ b/RxSwift/Observables/Using.swift
@@ -16,12 +16,12 @@ extension ObservableType {
      - parameter observableFactory: Factory function to obtain an observable sequence that depends on the obtained resource.
      - returns: An observable sequence whose lifetime controls the lifetime of the dependent resource object.
      */
-    public static func using<Resource: Disposable>(_ resourceFactory: @escaping () throws -> Resource, observableFactory: @escaping (Resource) throws -> Observable<Element>) -> Observable<Element> {
+    public static func using<Resource: Disposable>(_ resourceFactory: @escaping @Sendable () throws -> Resource, observableFactory: @escaping @Sendable (Resource) throws -> Observable<Element>) -> Observable<Element> {
         Using(resourceFactory: resourceFactory, observableFactory: observableFactory)
     }
 }
 
-final private class UsingSink<ResourceType: Disposable, Observer: ObserverType>: Sink<Observer>, ObserverType {
+final private class UsingSink<ResourceType: Disposable, Observer: ObserverType>: Sink<Observer>, ObserverType, @unchecked Sendable {
     typealias SourceType = Observer.Element 
     typealias Parent = Using<SourceType, ResourceType>
 
@@ -66,12 +66,12 @@ final private class UsingSink<ResourceType: Disposable, Observer: ObserverType>:
     }
 }
 
-final private class Using<SourceType, ResourceType: Disposable>: Producer<SourceType> {
+final private class Using<SourceType, ResourceType: Disposable>: Producer<SourceType>, @unchecked Sendable {
     
     typealias Element = SourceType
     
-    typealias ResourceFactory = () throws -> ResourceType
-    typealias ObservableFactory = (ResourceType) throws -> Observable<SourceType>
+    typealias ResourceFactory = @Sendable () throws -> ResourceType
+    typealias ObservableFactory = @Sendable (ResourceType) throws -> Observable<SourceType>
     
     fileprivate let resourceFactory: ResourceFactory
     fileprivate let observableFactory: ObservableFactory
diff --git a/RxSwift/Observables/Window.swift b/RxSwift/Observables/Window.swift
index c52dd3f49..d1092e121 100644
--- a/RxSwift/Observables/Window.swift
+++ b/RxSwift/Observables/Window.swift
@@ -30,7 +30,8 @@ final private class WindowTimeCountSink<Element, Observer: ObserverType>
     : Sink<Observer>
     , ObserverType
     , LockOwnerType
-    , SynchronizedOnType where Observer.Element == Observable<Element> {
+    , SynchronizedOnType
+    , @unchecked Sendable where Observer.Element == Observable<Element> {
     typealias Parent = WindowTimeCount<Element>
     
     private let parent: Parent
@@ -149,7 +150,7 @@ final private class WindowTimeCountSink<Element, Observer: ObserverType>
     }
 }
 
-final private class WindowTimeCount<Element>: Producer<Observable<Element>> {
+final private class WindowTimeCount<Element>: Producer<Observable<Element>>, @unchecked Sendable {
     fileprivate let timeSpan: RxTimeInterval
     fileprivate let count: Int
     fileprivate let scheduler: SchedulerType
diff --git a/RxSwift/Observables/WithLatestFrom.swift b/RxSwift/Observables/WithLatestFrom.swift
index d2868121a..358492507 100644
--- a/RxSwift/Observables/WithLatestFrom.swift
+++ b/RxSwift/Observables/WithLatestFrom.swift
@@ -18,7 +18,7 @@ extension ObservableType {
      - parameter resultSelector: Function to invoke for each element from the self combined with the latest element from the second source, if any.
      - returns: An observable sequence containing the result of combining each element of the self  with the latest element from the second source, if any, using the specified result selector function.
      */
-    public func withLatestFrom<Source: ObservableConvertibleType, ResultType>(_ second: Source, resultSelector: @escaping (Element, Source.Element) throws -> ResultType) -> Observable<ResultType> {
+    public func withLatestFrom<Source: ObservableConvertibleType, ResultType>(_ second: Source, resultSelector: @escaping @Sendable (Element, Source.Element) throws -> ResultType) -> Observable<ResultType> {
         WithLatestFrom(first: self.asObservable(), second: second.asObservable(), resultSelector: resultSelector)
     }
 
@@ -40,7 +40,8 @@ final private class WithLatestFromSink<FirstType, SecondType, Observer: Observer
     : Sink<Observer>
     , ObserverType
     , LockOwnerType
-    , SynchronizedOnType {
+    , SynchronizedOnType
+    , @unchecked Sendable {
     typealias ResultType = Observer.Element
     typealias Parent = WithLatestFrom<FirstType, SecondType, ResultType>
     typealias Element = FirstType
@@ -130,8 +131,8 @@ final private class WithLatestFromSecond<FirstType, SecondType, Observer: Observ
     }
 }
 
-final private class WithLatestFrom<FirstType, SecondType, ResultType>: Producer<ResultType> {
-    typealias ResultSelector = (FirstType, SecondType) throws -> ResultType
+final private class WithLatestFrom<FirstType, SecondType, ResultType>: Producer<ResultType>, @unchecked Sendable {
+    typealias ResultSelector = @Sendable (FirstType, SecondType) throws -> ResultType
     
     fileprivate let first: Observable<FirstType>
     fileprivate let second: Observable<SecondType>
diff --git a/RxSwift/Observables/WithUnretained.swift b/RxSwift/Observables/WithUnretained.swift
index 8466e89c5..2201ad635 100644
--- a/RxSwift/Observables/WithUnretained.swift
+++ b/RxSwift/Observables/WithUnretained.swift
@@ -20,7 +20,7 @@ extension ObservableType {
      */
     public func withUnretained<Object: AnyObject, Out>(
         _ obj: Object,
-        resultSelector: @escaping (Object, Element) -> Out
+        resultSelector: @escaping @Sendable (Object, Element) -> Out
     ) -> Observable<Out> {
         map { [weak obj] element -> Out in
             guard let obj = obj else { throw UnretainedError.failedRetaining }
diff --git a/RxSwift/Observables/Zip+Collection.swift b/RxSwift/Observables/Zip+Collection.swift
index 2d7f8877c..719d948cb 100644
--- a/RxSwift/Observables/Zip+Collection.swift
+++ b/RxSwift/Observables/Zip+Collection.swift
@@ -15,7 +15,7 @@ extension ObservableType {
      - parameter resultSelector: Function to invoke for each series of elements at corresponding indexes in the sources.
      - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
      */
-    public static func zip<Collection: Swift.Collection>(_ collection: Collection, resultSelector: @escaping ([Collection.Element.Element]) throws -> Element) -> Observable<Element>
+    public static func zip<Collection: Swift.Collection>(_ collection: Collection, resultSelector: @escaping @Sendable ([Collection.Element.Element]) throws -> Element) -> Observable<Element>
         where Collection.Element: ObservableType {
         ZipCollectionType(sources: collection, resultSelector: resultSelector)
     }
@@ -35,8 +35,9 @@ extension ObservableType {
 }
 
 final private class ZipCollectionTypeSink<Collection: Swift.Collection, Observer: ObserverType>
-    : Sink<Observer> where Collection.Element: ObservableConvertibleType {
-    typealias Result = Observer.Element 
+    : Sink<Observer>
+    , @unchecked Sendable where Collection.Element: ObservableConvertibleType {
+    typealias Result = Observer.Element
     typealias Parent = ZipCollectionType<Collection, Result>
     typealias SourceElement = Collection.Element.Element
     
@@ -147,8 +148,8 @@ final private class ZipCollectionTypeSink<Collection: Swift.Collection, Observer
     }
 }
 
-final private class ZipCollectionType<Collection: Swift.Collection, Result>: Producer<Result> where Collection.Element: ObservableConvertibleType {
-    typealias ResultSelector = ([Collection.Element.Element]) throws -> Result
+final private class ZipCollectionType<Collection: Swift.Collection, Result>: Producer<Result>, @unchecked Sendable where Collection.Element: ObservableConvertibleType {
+    typealias ResultSelector = @Sendable ([Collection.Element.Element]) throws -> Result
     
     let sources: Collection
     let resultSelector: ResultSelector
diff --git a/RxSwift/Observables/Zip+arity.swift b/RxSwift/Observables/Zip+arity.swift
index b6d876d1d..941e560e1 100644
--- a/RxSwift/Observables/Zip+arity.swift
+++ b/RxSwift/Observables/Zip+arity.swift
@@ -21,7 +21,7 @@ extension ObservableType {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func zip<O1: ObservableType, O2: ObservableType>
-        (_ source1: O1, _ source2: O2, resultSelector: @escaping (O1.Element, O2.Element) throws -> Element)
+    (_ source1: O1, _ source2: O2, resultSelector: @escaping @Sendable (O1.Element, O2.Element) throws -> Element)
         -> Observable<Element> {
         return Zip2(
             source1: source1.asObservable(), source2: source2.asObservable(),
@@ -48,8 +48,8 @@ extension ObservableType where Element == Any {
     }
 }
 
-final class ZipSink2_<E1, E2, Observer: ObserverType> : ZipSink<Observer> {
-    typealias Result = Observer.Element 
+final class ZipSink2_<E1, E2, Observer: ObserverType> : ZipSink<Observer>, @unchecked Sendable {
+    typealias Result = Observer.Element
     typealias Parent = Zip2<E1, E2, Result>
 
     let parent: Parent
@@ -93,8 +93,8 @@ final class ZipSink2_<E1, E2, Observer: ObserverType> : ZipSink<Observer> {
     }
 }
 
-final class Zip2<E1, E2, Result> : Producer<Result> {
-    typealias ResultSelector = (E1, E2) throws -> Result
+final class Zip2<E1, E2, Result> : Producer<Result>, @unchecked Sendable {
+    typealias ResultSelector = @Sendable (E1, E2) throws -> Result
 
     let source1: Observable<E1>
     let source2: Observable<E2>
@@ -129,7 +129,7 @@ extension ObservableType {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func zip<O1: ObservableType, O2: ObservableType, O3: ObservableType>
-        (_ source1: O1, _ source2: O2, _ source3: O3, resultSelector: @escaping (O1.Element, O2.Element, O3.Element) throws -> Element)
+    (_ source1: O1, _ source2: O2, _ source3: O3, resultSelector: @escaping @Sendable (O1.Element, O2.Element, O3.Element) throws -> Element)
         -> Observable<Element> {
         return Zip3(
             source1: source1.asObservable(), source2: source2.asObservable(), source3: source3.asObservable(),
@@ -156,8 +156,8 @@ extension ObservableType where Element == Any {
     }
 }
 
-final class ZipSink3_<E1, E2, E3, Observer: ObserverType> : ZipSink<Observer> {
-    typealias Result = Observer.Element 
+final class ZipSink3_<E1, E2, E3, Observer: ObserverType> : ZipSink<Observer>, @unchecked Sendable {
+    typealias Result = Observer.Element
     typealias Parent = Zip3<E1, E2, E3, Result>
 
     let parent: Parent
@@ -207,8 +207,8 @@ final class ZipSink3_<E1, E2, E3, Observer: ObserverType> : ZipSink<Observer> {
     }
 }
 
-final class Zip3<E1, E2, E3, Result> : Producer<Result> {
-    typealias ResultSelector = (E1, E2, E3) throws -> Result
+final class Zip3<E1, E2, E3, Result> : Producer<Result>, @unchecked Sendable {
+    typealias ResultSelector = @Sendable (E1, E2, E3) throws -> Result
 
     let source1: Observable<E1>
     let source2: Observable<E2>
@@ -245,7 +245,7 @@ extension ObservableType {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func zip<O1: ObservableType, O2: ObservableType, O3: ObservableType, O4: ObservableType>
-        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, resultSelector: @escaping (O1.Element, O2.Element, O3.Element, O4.Element) throws -> Element)
+    (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, resultSelector: @escaping @Sendable (O1.Element, O2.Element, O3.Element, O4.Element) throws -> Element)
         -> Observable<Element> {
         return Zip4(
             source1: source1.asObservable(), source2: source2.asObservable(), source3: source3.asObservable(), source4: source4.asObservable(),
@@ -272,7 +272,7 @@ extension ObservableType where Element == Any {
     }
 }
 
-final class ZipSink4_<E1, E2, E3, E4, Observer: ObserverType> : ZipSink<Observer> {
+final class ZipSink4_<E1, E2, E3, E4, Observer: ObserverType> : ZipSink<Observer>, @unchecked Sendable {
     typealias Result = Observer.Element 
     typealias Parent = Zip4<E1, E2, E3, E4, Result>
 
@@ -329,8 +329,8 @@ final class ZipSink4_<E1, E2, E3, E4, Observer: ObserverType> : ZipSink<Observer
     }
 }
 
-final class Zip4<E1, E2, E3, E4, Result> : Producer<Result> {
-    typealias ResultSelector = (E1, E2, E3, E4) throws -> Result
+final class Zip4<E1, E2, E3, E4, Result> : Producer<Result>, @unchecked Sendable {
+    typealias ResultSelector = @Sendable (E1, E2, E3, E4) throws -> Result
 
     let source1: Observable<E1>
     let source2: Observable<E2>
@@ -369,7 +369,7 @@ extension ObservableType {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func zip<O1: ObservableType, O2: ObservableType, O3: ObservableType, O4: ObservableType, O5: ObservableType>
-        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, resultSelector: @escaping (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element) throws -> Element)
+    (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, resultSelector: @escaping @Sendable (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element) throws -> Element)
         -> Observable<Element> {
         return Zip5(
             source1: source1.asObservable(), source2: source2.asObservable(), source3: source3.asObservable(), source4: source4.asObservable(), source5: source5.asObservable(),
@@ -396,8 +396,8 @@ extension ObservableType where Element == Any {
     }
 }
 
-final class ZipSink5_<E1, E2, E3, E4, E5, Observer: ObserverType> : ZipSink<Observer> {
-    typealias Result = Observer.Element 
+final class ZipSink5_<E1, E2, E3, E4, E5, Observer: ObserverType> : ZipSink<Observer>, @unchecked Sendable {
+    typealias Result = Observer.Element
     typealias Parent = Zip5<E1, E2, E3, E4, E5, Result>
 
     let parent: Parent
@@ -459,8 +459,8 @@ final class ZipSink5_<E1, E2, E3, E4, E5, Observer: ObserverType> : ZipSink<Obse
     }
 }
 
-final class Zip5<E1, E2, E3, E4, E5, Result> : Producer<Result> {
-    typealias ResultSelector = (E1, E2, E3, E4, E5) throws -> Result
+final class Zip5<E1, E2, E3, E4, E5, Result> : Producer<Result>, @unchecked Sendable {
+    typealias ResultSelector = @Sendable (E1, E2, E3, E4, E5) throws -> Result
 
     let source1: Observable<E1>
     let source2: Observable<E2>
@@ -501,7 +501,7 @@ extension ObservableType {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func zip<O1: ObservableType, O2: ObservableType, O3: ObservableType, O4: ObservableType, O5: ObservableType, O6: ObservableType>
-        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, _ source6: O6, resultSelector: @escaping (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element, O6.Element) throws -> Element)
+    (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, _ source6: O6, resultSelector: @escaping @Sendable (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element, O6.Element) throws -> Element)
         -> Observable<Element> {
         return Zip6(
             source1: source1.asObservable(), source2: source2.asObservable(), source3: source3.asObservable(), source4: source4.asObservable(), source5: source5.asObservable(), source6: source6.asObservable(),
@@ -528,8 +528,8 @@ extension ObservableType where Element == Any {
     }
 }
 
-final class ZipSink6_<E1, E2, E3, E4, E5, E6, Observer: ObserverType> : ZipSink<Observer> {
-    typealias Result = Observer.Element 
+final class ZipSink6_<E1, E2, E3, E4, E5, E6, Observer: ObserverType> : ZipSink<Observer>, @unchecked Sendable {
+    typealias Result = Observer.Element
     typealias Parent = Zip6<E1, E2, E3, E4, E5, E6, Result>
 
     let parent: Parent
@@ -597,8 +597,8 @@ final class ZipSink6_<E1, E2, E3, E4, E5, E6, Observer: ObserverType> : ZipSink<
     }
 }
 
-final class Zip6<E1, E2, E3, E4, E5, E6, Result> : Producer<Result> {
-    typealias ResultSelector = (E1, E2, E3, E4, E5, E6) throws -> Result
+final class Zip6<E1, E2, E3, E4, E5, E6, Result> : Producer<Result>, @unchecked Sendable {
+    typealias ResultSelector = @Sendable (E1, E2, E3, E4, E5, E6) throws -> Result
 
     let source1: Observable<E1>
     let source2: Observable<E2>
@@ -641,7 +641,7 @@ extension ObservableType {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func zip<O1: ObservableType, O2: ObservableType, O3: ObservableType, O4: ObservableType, O5: ObservableType, O6: ObservableType, O7: ObservableType>
-        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, _ source6: O6, _ source7: O7, resultSelector: @escaping (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element, O6.Element, O7.Element) throws -> Element)
+    (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, _ source6: O6, _ source7: O7, resultSelector: @escaping @Sendable (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element, O6.Element, O7.Element) throws -> Element)
         -> Observable<Element> {
         return Zip7(
             source1: source1.asObservable(), source2: source2.asObservable(), source3: source3.asObservable(), source4: source4.asObservable(), source5: source5.asObservable(), source6: source6.asObservable(), source7: source7.asObservable(),
@@ -668,8 +668,8 @@ extension ObservableType where Element == Any {
     }
 }
 
-final class ZipSink7_<E1, E2, E3, E4, E5, E6, E7, Observer: ObserverType> : ZipSink<Observer> {
-    typealias Result = Observer.Element 
+final class ZipSink7_<E1, E2, E3, E4, E5, E6, E7, Observer: ObserverType> : ZipSink<Observer>, @unchecked Sendable {
+    typealias Result = Observer.Element
     typealias Parent = Zip7<E1, E2, E3, E4, E5, E6, E7, Result>
 
     let parent: Parent
@@ -743,8 +743,8 @@ final class ZipSink7_<E1, E2, E3, E4, E5, E6, E7, Observer: ObserverType> : ZipS
     }
 }
 
-final class Zip7<E1, E2, E3, E4, E5, E6, E7, Result> : Producer<Result> {
-    typealias ResultSelector = (E1, E2, E3, E4, E5, E6, E7) throws -> Result
+final class Zip7<E1, E2, E3, E4, E5, E6, E7, Result> : Producer<Result>, @unchecked Sendable {
+    typealias ResultSelector = @Sendable (E1, E2, E3, E4, E5, E6, E7) throws -> Result
 
     let source1: Observable<E1>
     let source2: Observable<E2>
@@ -789,7 +789,7 @@ extension ObservableType {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func zip<O1: ObservableType, O2: ObservableType, O3: ObservableType, O4: ObservableType, O5: ObservableType, O6: ObservableType, O7: ObservableType, O8: ObservableType>
-        (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, _ source6: O6, _ source7: O7, _ source8: O8, resultSelector: @escaping (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element, O6.Element, O7.Element, O8.Element) throws -> Element)
+    (_ source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, _ source6: O6, _ source7: O7, _ source8: O8, resultSelector: @escaping @Sendable (O1.Element, O2.Element, O3.Element, O4.Element, O5.Element, O6.Element, O7.Element, O8.Element) throws -> Element)
         -> Observable<Element> {
         return Zip8(
             source1: source1.asObservable(), source2: source2.asObservable(), source3: source3.asObservable(), source4: source4.asObservable(), source5: source5.asObservable(), source6: source6.asObservable(), source7: source7.asObservable(), source8: source8.asObservable(),
@@ -816,7 +816,7 @@ extension ObservableType where Element == Any {
     }
 }
 
-final class ZipSink8_<E1, E2, E3, E4, E5, E6, E7, E8, Observer: ObserverType> : ZipSink<Observer> {
+final class ZipSink8_<E1, E2, E3, E4, E5, E6, E7, E8, Observer: ObserverType> : ZipSink<Observer>, @unchecked Sendable {
     typealias Result = Observer.Element 
     typealias Parent = Zip8<E1, E2, E3, E4, E5, E6, E7, E8, Result>
 
@@ -897,8 +897,8 @@ final class ZipSink8_<E1, E2, E3, E4, E5, E6, E7, E8, Observer: ObserverType> :
     }
 }
 
-final class Zip8<E1, E2, E3, E4, E5, E6, E7, E8, Result> : Producer<Result> {
-    typealias ResultSelector = (E1, E2, E3, E4, E5, E6, E7, E8) throws -> Result
+final class Zip8<E1, E2, E3, E4, E5, E6, E7, E8, Result> : Producer<Result>, @unchecked Sendable {
+    typealias ResultSelector = @Sendable (E1, E2, E3, E4, E5, E6, E7, E8) throws -> Result
 
     let source1: Observable<E1>
     let source2: Observable<E2>
diff --git a/RxSwift/Observables/Zip.swift b/RxSwift/Observables/Zip.swift
index 328a40ef7..300e4fc42 100644
--- a/RxSwift/Observables/Zip.swift
+++ b/RxSwift/Observables/Zip.swift
@@ -12,7 +12,7 @@ protocol ZipSinkProtocol: AnyObject {
     func done(_ index: Int)
 }
 
-class ZipSink<Observer: ObserverType> : Sink<Observer>, ZipSinkProtocol {
+class ZipSink<Observer: ObserverType> : Sink<Observer>, ZipSinkProtocol, @unchecked Sendable {
     typealias Element = Observer.Element
     
     let arity: Int
@@ -84,8 +84,9 @@ class ZipSink<Observer: ObserverType> : Sink<Observer>, ZipSinkProtocol {
 final class ZipObserver<Element>
     : ObserverType
     , LockOwnerType
-    , SynchronizedOnType {
-    typealias ValueSetter = (Element) -> Void
+    , SynchronizedOnType
+    , @unchecked Sendable {
+    typealias ValueSetter = @Sendable (Element) -> Void
 
     private var parent: ZipSinkProtocol?
     
diff --git a/RxSwift/ObserverType.swift b/RxSwift/ObserverType.swift
index b7a66480e..e6817dc2f 100644
--- a/RxSwift/ObserverType.swift
+++ b/RxSwift/ObserverType.swift
@@ -7,13 +7,14 @@
 //
 
 /// Supports push-style iteration over an observable sequence.
-public protocol ObserverType {
+public protocol ObserverType: Sendable {
     /// The type of elements in sequence that observer can observe.
     associatedtype Element
 
     /// Notify observer about sequence event.
     ///
     /// - parameter event: Event that occurred.
+    @Sendable
     func on(_ event: Event<Element>)
 }
 
diff --git a/RxSwift/Observers/AnonymousObserver.swift b/RxSwift/Observers/AnonymousObserver.swift
index cbb42dc82..4851207b7 100644
--- a/RxSwift/Observers/AnonymousObserver.swift
+++ b/RxSwift/Observers/AnonymousObserver.swift
@@ -6,8 +6,8 @@
 //  Copyright © 2015 Krunoslav Zaher. All rights reserved.
 //
 
-final class AnonymousObserver<Element>: ObserverBase<Element> {
-    typealias EventHandler = (Event<Element>) -> Void
+final class AnonymousObserver<Element>: ObserverBase<Element>, @unchecked Sendable {
+    typealias EventHandler = @Sendable (Event<Element>) -> Void
     
     private let eventHandler : EventHandler
     
diff --git a/RxSwift/Observers/ObserverBase.swift b/RxSwift/Observers/ObserverBase.swift
index 48e09868b..625f2e859 100644
--- a/RxSwift/Observers/ObserverBase.swift
+++ b/RxSwift/Observers/ObserverBase.swift
@@ -6,7 +6,7 @@
 //  Copyright © 2015 Krunoslav Zaher. All rights reserved.
 //
 
-class ObserverBase<Element> : Disposable, ObserverType {
+class ObserverBase<Element> : Disposable, ObserverType, @unchecked Sendable {
     private let isStopped = AtomicInt(0)
 
     func on(_ event: Event<Element>) {
diff --git a/RxSwift/Observers/TailRecursiveSink.swift b/RxSwift/Observers/TailRecursiveSink.swift
index fd527001d..7f01ffcf2 100644
--- a/RxSwift/Observers/TailRecursiveSink.swift
+++ b/RxSwift/Observers/TailRecursiveSink.swift
@@ -18,7 +18,8 @@ enum TailRecursiveSinkCommand {
 /// This class is usually used with `Generator` version of the operators.
 class TailRecursiveSink<Sequence: Swift.Sequence, Observer: ObserverType>
     : Sink<Observer>
-    , InvocableWithValueType where Sequence.Element: ObservableConvertibleType, Sequence.Element.Element == Observer.Element {
+    , InvocableWithValueType
+    , @unchecked Sendable where Sequence.Element: ObservableConvertibleType, Sequence.Element.Element == Observer.Element {
     typealias Value = TailRecursiveSinkCommand
     typealias Element = Observer.Element 
     typealias SequenceGenerator = (generator: Sequence.Iterator, remaining: IntMax?)
diff --git a/RxSwift/SchedulerType.swift b/RxSwift/SchedulerType.swift
index 6c8fe4a38..478b62bff 100644
--- a/RxSwift/SchedulerType.swift
+++ b/RxSwift/SchedulerType.swift
@@ -31,7 +31,7 @@ public protocol SchedulerType: ImmediateSchedulerType {
     - parameter action: Action to be executed.
     - returns: The disposable object used to cancel the scheduled action (best effort).
     */
-    func scheduleRelative<StateType>(_ state: StateType, dueTime: RxTimeInterval, action: @escaping (StateType) -> Disposable) -> Disposable
+    func scheduleRelative<StateType>(_ state: StateType, dueTime: RxTimeInterval, action: @escaping @Sendable (StateType) -> Disposable) -> Disposable
  
     /**
     Schedules a periodic piece of work.
@@ -42,7 +42,7 @@ public protocol SchedulerType: ImmediateSchedulerType {
     - parameter action: Action to be executed.
     - returns: The disposable object used to cancel the scheduled action (best effort).
     */
-    func schedulePeriodic<StateType>(_ state: StateType, startAfter: RxTimeInterval, period: RxTimeInterval, action: @escaping (StateType) -> StateType) -> Disposable
+    func schedulePeriodic<StateType>(_ state: StateType, startAfter: RxTimeInterval, period: RxTimeInterval, action: @escaping @Sendable (StateType) -> StateType) -> Disposable
 }
 
 extension SchedulerType {
@@ -55,13 +55,13 @@ extension SchedulerType {
     - parameter period: Period for running the work periodically.
     - returns: The disposable object used to cancel the scheduled recurring action (best effort).
     */
-    public func schedulePeriodic<StateType>(_ state: StateType, startAfter: RxTimeInterval, period: RxTimeInterval, action: @escaping (StateType) -> StateType) -> Disposable {
+    public func schedulePeriodic<StateType>(_ state: StateType, startAfter: RxTimeInterval, period: RxTimeInterval, action: @escaping @Sendable (StateType) -> StateType) -> Disposable {
         let schedule = SchedulePeriodicRecursive(scheduler: self, startAfter: startAfter, period: period, action: action, state: state)
             
         return schedule.start()
     }
 
-    func scheduleRecursive<State>(_ state: State, dueTime: RxTimeInterval, action: @escaping (State, AnyRecursiveScheduler<State>) -> Void) -> Disposable {
+    func scheduleRecursive<State>(_ state: State, dueTime: RxTimeInterval, action: @escaping @Sendable (State, AnyRecursiveScheduler<State>) -> Void) -> Disposable {
         let scheduler = AnyRecursiveScheduler(scheduler: self, action: action)
          
         scheduler.schedule(state, dueTime: dueTime)
diff --git a/RxSwift/Schedulers/ConcurrentDispatchQueueScheduler.swift b/RxSwift/Schedulers/ConcurrentDispatchQueueScheduler.swift
index 02c47c917..51fc07432 100644
--- a/RxSwift/Schedulers/ConcurrentDispatchQueueScheduler.swift
+++ b/RxSwift/Schedulers/ConcurrentDispatchQueueScheduler.swift
@@ -12,7 +12,7 @@ import Foundation
 /// Abstracts the work that needs to be performed on a specific `dispatch_queue_t`. You can also pass a serial dispatch queue, it shouldn't cause any problems.
 ///
 /// This scheduler is suitable when some work needs to be performed in background.
-public class ConcurrentDispatchQueueScheduler: SchedulerType {
+public class ConcurrentDispatchQueueScheduler: SchedulerType, @unchecked Sendable {
     public typealias TimeInterval = Foundation.TimeInterval
     public typealias Time = Date
     
@@ -51,7 +51,7 @@ public class ConcurrentDispatchQueueScheduler: SchedulerType {
     - parameter action: Action to be executed.
     - returns: The disposable object used to cancel the scheduled action (best effort).
     */
-    public final func schedule<StateType>(_ state: StateType, action: @escaping (StateType) -> Disposable) -> Disposable {
+    public final func schedule<StateType>(_ state: StateType, action: @escaping @Sendable (StateType) -> Disposable) -> Disposable {
         self.configuration.schedule(state, action: action)
     }
     
@@ -63,7 +63,7 @@ public class ConcurrentDispatchQueueScheduler: SchedulerType {
     - parameter action: Action to be executed.
     - returns: The disposable object used to cancel the scheduled action (best effort).
     */
-    public final func scheduleRelative<StateType>(_ state: StateType, dueTime: RxTimeInterval, action: @escaping (StateType) -> Disposable) -> Disposable {
+    public final func scheduleRelative<StateType>(_ state: StateType, dueTime: RxTimeInterval, action: @escaping @Sendable (StateType) -> Disposable) -> Disposable {
         self.configuration.scheduleRelative(state, dueTime: dueTime, action: action)
     }
     
@@ -76,7 +76,7 @@ public class ConcurrentDispatchQueueScheduler: SchedulerType {
     - parameter action: Action to be executed.
     - returns: The disposable object used to cancel the scheduled action (best effort).
     */
-    public func schedulePeriodic<StateType>(_ state: StateType, startAfter: RxTimeInterval, period: RxTimeInterval, action: @escaping (StateType) -> StateType) -> Disposable {
+    public func schedulePeriodic<StateType>(_ state: StateType, startAfter: RxTimeInterval, period: RxTimeInterval, action: @escaping @Sendable (StateType) -> StateType) -> Disposable {
         self.configuration.schedulePeriodic(state, startAfter: startAfter, period: period, action: action)
     }
 }
diff --git a/RxSwift/Schedulers/ConcurrentMainScheduler.swift b/RxSwift/Schedulers/ConcurrentMainScheduler.swift
index c438d7d4d..8d1e5a11b 100644
--- a/RxSwift/Schedulers/ConcurrentMainScheduler.swift
+++ b/RxSwift/Schedulers/ConcurrentMainScheduler.swift
@@ -42,14 +42,14 @@ public final class ConcurrentMainScheduler : SchedulerType {
     - parameter action: Action to be executed.
     - returns: The disposable object used to cancel the scheduled action (best effort).
     */
-    public func schedule<StateType>(_ state: StateType, action: @escaping (StateType) -> Disposable) -> Disposable {
+    public func schedule<StateType>(_ state: StateType, action: @escaping @Sendable (StateType) -> Disposable) -> Disposable {
         if DispatchQueue.isMain {
             return action(state)
         }
 
         let cancel = SingleAssignmentDisposable()
 
-        self.mainQueue.async {
+        self.mainQueue.async { @Sendable () in
             if cancel.isDisposed {
                 return
             }
@@ -68,7 +68,7 @@ public final class ConcurrentMainScheduler : SchedulerType {
     - parameter action: Action to be executed.
     - returns: The disposable object used to cancel the scheduled action (best effort).
     */
-    public final func scheduleRelative<StateType>(_ state: StateType, dueTime: RxTimeInterval, action: @escaping (StateType) -> Disposable) -> Disposable {
+    public final func scheduleRelative<StateType>(_ state: StateType, dueTime: RxTimeInterval, action: @escaping @Sendable (StateType) -> Disposable) -> Disposable {
         self.mainScheduler.scheduleRelative(state, dueTime: dueTime, action: action)
     }
 
@@ -81,7 +81,7 @@ public final class ConcurrentMainScheduler : SchedulerType {
     - parameter action: Action to be executed.
     - returns: The disposable object used to cancel the scheduled action (best effort).
     */
-    public func schedulePeriodic<StateType>(_ state: StateType, startAfter: RxTimeInterval, period: RxTimeInterval, action: @escaping (StateType) -> StateType) -> Disposable {
+    public func schedulePeriodic<StateType>(_ state: StateType, startAfter: RxTimeInterval, period: RxTimeInterval, action: @escaping @Sendable (StateType) -> StateType) -> Disposable {
         self.mainScheduler.schedulePeriodic(state, startAfter: startAfter, period: period, action: action)
     }
 }
diff --git a/RxSwift/Schedulers/CurrentThreadScheduler.swift b/RxSwift/Schedulers/CurrentThreadScheduler.swift
index 16a7dd328..d80dc9725 100644
--- a/RxSwift/Schedulers/CurrentThreadScheduler.swift
+++ b/RxSwift/Schedulers/CurrentThreadScheduler.swift
@@ -35,7 +35,7 @@ import Foundation
 /// This is the default scheduler for operators that generate elements.
 ///
 /// This scheduler is also sometimes called `trampoline scheduler`.
-public class CurrentThreadScheduler : ImmediateSchedulerType {
+public class CurrentThreadScheduler : ImmediateSchedulerType, @unchecked Sendable {
     typealias ScheduleQueue = RxMutableBox<Queue<ScheduledItemType>>
 
     /// The singleton instance of the current thread scheduler.
@@ -87,7 +87,7 @@ public class CurrentThreadScheduler : ImmediateSchedulerType {
     - parameter action: Action to be executed.
     - returns: The disposable object used to cancel the scheduled action (best effort).
     */
-    public func schedule<StateType>(_ state: StateType, action: @escaping (StateType) -> Disposable) -> Disposable {
+    public func schedule<StateType>(_ state: StateType, action: @escaping @Sendable (StateType) -> Disposable) -> Disposable {
         if CurrentThreadScheduler.isScheduleRequired {
             CurrentThreadScheduler.isScheduleRequired = false
 
diff --git a/RxSwift/Schedulers/HistoricalScheduler.swift b/RxSwift/Schedulers/HistoricalScheduler.swift
index 254a3e83c..204b2f3a2 100644
--- a/RxSwift/Schedulers/HistoricalScheduler.swift
+++ b/RxSwift/Schedulers/HistoricalScheduler.swift
@@ -9,7 +9,7 @@
 import Foundation
 
 /// Provides a virtual time scheduler that uses `Date` for absolute time and `TimeInterval` for relative time.
-public class HistoricalScheduler : VirtualTimeScheduler<HistoricalSchedulerTimeConverter> {
+public class HistoricalScheduler : VirtualTimeScheduler<HistoricalSchedulerTimeConverter>, @unchecked Sendable {
 
     /**
       Creates a new historical scheduler with initial clock value.
diff --git a/RxSwift/Schedulers/Internal/DispatchQueueConfiguration.swift b/RxSwift/Schedulers/Internal/DispatchQueueConfiguration.swift
index 53f148dc4..779257a73 100644
--- a/RxSwift/Schedulers/Internal/DispatchQueueConfiguration.swift
+++ b/RxSwift/Schedulers/Internal/DispatchQueueConfiguration.swift
@@ -15,10 +15,10 @@ struct DispatchQueueConfiguration {
 }
 
 extension DispatchQueueConfiguration {
-    func schedule<StateType>(_ state: StateType, action: @escaping (StateType) -> Disposable) -> Disposable {
+    func schedule<StateType>(_ state: StateType, action: @escaping @Sendable (StateType) -> Disposable) -> Disposable {
         let cancel = SingleAssignmentDisposable()
 
-        self.queue.async {
+        self.queue.async { @Sendable () in
             if cancel.isDisposed {
                 return
             }
@@ -30,7 +30,7 @@ extension DispatchQueueConfiguration {
         return cancel
     }
 
-    func scheduleRelative<StateType>(_ state: StateType, dueTime: RxTimeInterval, action: @escaping (StateType) -> Disposable) -> Disposable {
+    func scheduleRelative<StateType>(_ state: StateType, dueTime: RxTimeInterval, action: @escaping @Sendable (StateType) -> Disposable) -> Disposable {
         let deadline = DispatchTime.now() + dueTime
 
         let compositeDisposable = CompositeDisposable()
@@ -44,13 +44,13 @@ extension DispatchQueueConfiguration {
         // Need more info on this.
         // It looks like just setting timer to fire and not holding a reference to it
         // until deadline causes timer cancellation.
-        var timerReference: DispatchSourceTimer? = timer
+        nonisolated(unsafe) var timerReference: DispatchSourceTimer? = timer
         let cancelTimer = Disposables.create {
             timerReference?.cancel()
             timerReference = nil
         }
 
-        timer.setEventHandler(handler: {
+        timer.setEventHandler(handler: { @Sendable () in
             if compositeDisposable.isDisposed {
                 return
             }
@@ -64,10 +64,10 @@ extension DispatchQueueConfiguration {
         return compositeDisposable
     }
 
-    func schedulePeriodic<StateType>(_ state: StateType, startAfter: RxTimeInterval, period: RxTimeInterval, action: @escaping (StateType) -> StateType) -> Disposable {
+    func schedulePeriodic<StateType>(_ state: StateType, startAfter: RxTimeInterval, period: RxTimeInterval, action: @escaping @Sendable (StateType) -> StateType) -> Disposable {
         let initial = DispatchTime.now() + startAfter
 
-        var timerState = state
+        nonisolated(unsafe) var timerState = state
 
         let timer = DispatchSource.makeTimerSource(queue: self.queue)
         timer.schedule(deadline: initial, repeating: period, leeway: self.leeway)
@@ -78,13 +78,13 @@ extension DispatchQueueConfiguration {
         // Need more info on this.
         // It looks like just setting timer to fire and not holding a reference to it
         // until deadline causes timer cancellation.
-        var timerReference: DispatchSourceTimer? = timer
+        nonisolated(unsafe) var timerReference: DispatchSourceTimer? = timer
         let cancelTimer = Disposables.create {
             timerReference?.cancel()
             timerReference = nil
         }
 
-        timer.setEventHandler(handler: {
+        timer.setEventHandler(handler: { @Sendable () in
             if cancelTimer.isDisposed {
                 return
             }
diff --git a/RxSwift/Schedulers/Internal/ScheduledItem.swift b/RxSwift/Schedulers/Internal/ScheduledItem.swift
index 3d790d7af..f4724bf27 100644
--- a/RxSwift/Schedulers/Internal/ScheduledItem.swift
+++ b/RxSwift/Schedulers/Internal/ScheduledItem.swift
@@ -8,8 +8,9 @@
 
 struct ScheduledItem<T>
     : ScheduledItemType
-    , InvocableType {
-    typealias Action = (T) -> Disposable
+    , InvocableType
+    , @unchecked Sendable {
+    typealias Action = @Sendable (T) -> Disposable
     
     private let action: Action
     private let state: T
diff --git a/RxSwift/Schedulers/MainScheduler.swift b/RxSwift/Schedulers/MainScheduler.swift
index f6a507f3f..4ac402409 100644
--- a/RxSwift/Schedulers/MainScheduler.swift
+++ b/RxSwift/Schedulers/MainScheduler.swift
@@ -21,7 +21,7 @@ Main scheduler is a specialization of `SerialDispatchQueueScheduler`.
 This scheduler is optimized for `observeOn` operator. To ensure observable sequence is subscribed on main thread using `subscribeOn`
 operator please use `ConcurrentMainScheduler` because it is more optimized for that purpose.
 */
-public final class MainScheduler : SerialDispatchQueueScheduler {
+public final class MainScheduler : SerialDispatchQueueScheduler, @unchecked Sendable {
 
     private let mainQueue: DispatchQueue
 
@@ -56,7 +56,7 @@ public final class MainScheduler : SerialDispatchQueueScheduler {
         #endif
     }
 
-    override func scheduleInternal<StateType>(_ state: StateType, action: @escaping (StateType) -> Disposable) -> Disposable {
+    override func scheduleInternal<StateType>(_ state: StateType, action: @escaping @Sendable (StateType) -> Disposable) -> Disposable {
         let previousNumberEnqueued = increment(self.numberEnqueued)
 
         if DispatchQueue.isMain && previousNumberEnqueued == 0 {
@@ -78,3 +78,42 @@ public final class MainScheduler : SerialDispatchQueueScheduler {
         return cancel
     }
 }
+
+extension MainScheduler {
+    // implementation copied from from assumeIsolated. This is copied because assumeIsolated has @available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *). This implementation also remove the check that the closure is executed on the main actor.
+    @preconcurrency nonisolated
+    static private func _assumeMainActor<T>(execute operation: @MainActor(unsafe) () throws -> T) rethrows -> T {
+        typealias YesActor = @MainActor () throws -> T
+        typealias NoActor = () throws -> T
+        
+        // To do the unsafe cast, we have to pretend it's @escaping.
+        return try withoutActuallyEscaping(operation) { (_ fn: @escaping YesActor) throws -> T in
+            let rawFn = unsafeBitCast(fn, to: NoActor.self)
+            return try rawFn()
+        }
+    }
+    
+    @preconcurrency nonisolated
+    static public func assumeMainActor<T>(execute operation: @MainActor(unsafe) () throws -> T) rethrows -> T {
+        ensureRunningOnMainThread()
+        return try _assumeMainActor(execute: operation)
+    }
+    
+    public static func assumeMainActor<T>(_ work: @escaping @Sendable @MainActor(assumed) () -> T) -> (@Sendable () -> T) {
+        return { @Sendable () -> T in
+            return MainScheduler.assumeMainActor(execute: { return work() })
+        }
+    }
+    
+    public static func assumeMainActor<T, Value>(_ work: @escaping @Sendable @MainActor(assumed) (Value) -> T) -> (@Sendable (Value) -> T) {
+        return { @Sendable (value: Value) -> T in
+            return MainScheduler.assumeMainActor(execute: { return work(value) })
+        }
+    }
+    
+    public static func assumeMainActor<T, Value1, Value2>(_ work: @escaping @Sendable @MainActor(assumed) (Value1, Value2) -> T) -> (@Sendable (Value1, Value2) -> T) {
+        return { @Sendable (value1: Value1, value2: Value2) -> T in
+            return MainScheduler.assumeMainActor(execute: { return work(value1, value2) })
+        }
+    }
+}
diff --git a/RxSwift/Schedulers/OperationQueueScheduler.swift b/RxSwift/Schedulers/OperationQueueScheduler.swift
index f0ad3d3ce..c2984c929 100644
--- a/RxSwift/Schedulers/OperationQueueScheduler.swift
+++ b/RxSwift/Schedulers/OperationQueueScheduler.swift
@@ -12,7 +12,7 @@ import Foundation
 /// Abstracts the work that needs to be performed on a specific `NSOperationQueue`.
 ///
 /// This scheduler is suitable for cases when there is some bigger chunk of work that needs to be performed in background and you want to fine tune concurrent processing using `maxConcurrentOperationCount`.
-public class OperationQueueScheduler: ImmediateSchedulerType {
+public class OperationQueueScheduler: ImmediateSchedulerType, @unchecked Sendable {
     public let operationQueue: OperationQueue
     public let queuePriority: Operation.QueuePriority
     
@@ -32,7 +32,7 @@ public class OperationQueueScheduler: ImmediateSchedulerType {
     - parameter action: Action to execute recursively. The last parameter passed to the action is used to trigger recursive scheduling of the action, passing in recursive invocation state.
     - returns: The disposable object used to cancel the scheduled action (best effort).
     */
-    public func schedule<StateType>(_ state: StateType, action: @escaping (StateType) -> Disposable) -> Disposable {
+    public func schedule<StateType>(_ state: StateType, action: @escaping @Sendable (StateType) -> Disposable) -> Disposable {
         let cancel = SingleAssignmentDisposable()
 
         let operation = BlockOperation {
diff --git a/RxSwift/Schedulers/RecursiveScheduler.swift b/RxSwift/Schedulers/RecursiveScheduler.swift
index 0ee78cd18..a017fc4ef 100644
--- a/RxSwift/Schedulers/RecursiveScheduler.swift
+++ b/RxSwift/Schedulers/RecursiveScheduler.swift
@@ -37,7 +37,7 @@ final class AnyRecursiveScheduler<State> {
     - parameter dueTime: Relative time after which to execute the recursive action.
     */
     func schedule(_ state: State, dueTime: RxTimeInterval) {
-        var scheduleState: ScheduleState = .initial
+        nonisolated(unsafe) var scheduleState: ScheduleState = .initial
 
         let d = self.scheduler.scheduleRelative(state, dueTime: dueTime) { state -> Disposable in
             // best effort
@@ -88,7 +88,7 @@ final class AnyRecursiveScheduler<State> {
     ///
     /// - parameter state: State passed to the action to be executed.
     func schedule(_ state: State) {
-        var scheduleState: ScheduleState = .initial
+        nonisolated(unsafe) var scheduleState: ScheduleState = .initial
 
         let d = self.scheduler.schedule(state) { state -> Disposable in
             // best effort
@@ -135,6 +135,7 @@ final class AnyRecursiveScheduler<State> {
         }
     }
     
+    @Sendable
     func dispose() {
         self.lock.performLocked {
             self.action = nil
@@ -144,7 +145,7 @@ final class AnyRecursiveScheduler<State> {
 }
 
 /// Type erased recursive scheduler.
-final class RecursiveImmediateScheduler<State> {
+final class RecursiveImmediateScheduler<State>: @unchecked Sendable {
     typealias Action =  (_ state: State, _ recurse: (State) -> Void) -> Void
     
     private var lock = SpinLock()
@@ -164,7 +165,7 @@ final class RecursiveImmediateScheduler<State> {
     ///
     /// - parameter state: State passed to the action to be executed.
     func schedule(_ state: State) {
-        var scheduleState: ScheduleState = .initial
+        nonisolated(unsafe) var scheduleState: ScheduleState = .initial
 
         let d = self.scheduler.schedule(state) { state -> Disposable in
             // best effort
@@ -211,6 +212,7 @@ final class RecursiveImmediateScheduler<State> {
         }
     }
     
+    @Sendable
     func dispose() {
         self.lock.performLocked {
             self.action = nil
diff --git a/RxSwift/Schedulers/SchedulerServices+Emulation.swift b/RxSwift/Schedulers/SchedulerServices+Emulation.swift
index cab2bc8b3..81ae5ad93 100644
--- a/RxSwift/Schedulers/SchedulerServices+Emulation.swift
+++ b/RxSwift/Schedulers/SchedulerServices+Emulation.swift
@@ -12,7 +12,7 @@ enum SchedulePeriodicRecursiveCommand {
 }
 
 final class SchedulePeriodicRecursive<State> {
-    typealias RecursiveAction = (State) -> State
+    typealias RecursiveAction = @Sendable (State) -> State
     typealias RecursiveScheduler = AnyRecursiveScheduler<SchedulePeriodicRecursiveCommand>
 
     private let scheduler: SchedulerType
@@ -34,7 +34,8 @@ final class SchedulePeriodicRecursive<State> {
     func start() -> Disposable {
         self.scheduler.scheduleRecursive(SchedulePeriodicRecursiveCommand.tick, dueTime: self.startAfter, action: self.tick)
     }
-
+    
+    @Sendable
     func tick(_ command: SchedulePeriodicRecursiveCommand, scheduler: RecursiveScheduler) {
         // Tries to emulate periodic scheduling as best as possible.
         // The problem that could arise is if handling periodic ticks take too long, or
diff --git a/RxSwift/Schedulers/SerialDispatchQueueScheduler.swift b/RxSwift/Schedulers/SerialDispatchQueueScheduler.swift
index bb0013c8f..65225d6e0 100644
--- a/RxSwift/Schedulers/SerialDispatchQueueScheduler.swift
+++ b/RxSwift/Schedulers/SerialDispatchQueueScheduler.swift
@@ -26,7 +26,7 @@ In case some customization need to be made on it before usage,
 internal serial queue can be customized using `serialQueueConfiguration`
 callback.
 */
-public class SerialDispatchQueueScheduler : SchedulerType {
+public class SerialDispatchQueueScheduler : SchedulerType, @unchecked Sendable {
     public typealias TimeInterval = Foundation.TimeInterval
     public typealias Time = Date
     
@@ -96,11 +96,11 @@ public class SerialDispatchQueueScheduler : SchedulerType {
     - parameter action: Action to be executed.
     - returns: The disposable object used to cancel the scheduled action (best effort).
     */
-    public final func schedule<StateType>(_ state: StateType, action: @escaping (StateType) -> Disposable) -> Disposable {
+    public final func schedule<StateType>(_ state: StateType, action: @escaping @Sendable (StateType) -> Disposable) -> Disposable {
         self.scheduleInternal(state, action: action)
     }
 
-    func scheduleInternal<StateType>(_ state: StateType, action: @escaping (StateType) -> Disposable) -> Disposable {
+    func scheduleInternal<StateType>(_ state: StateType, action: @escaping @Sendable (StateType) -> Disposable) -> Disposable {
         self.configuration.schedule(state, action: action)
     }
 
@@ -112,7 +112,7 @@ public class SerialDispatchQueueScheduler : SchedulerType {
     - parameter action: Action to be executed.
     - returns: The disposable object used to cancel the scheduled action (best effort).
     */
-    public final func scheduleRelative<StateType>(_ state: StateType, dueTime: RxTimeInterval, action: @escaping (StateType) -> Disposable) -> Disposable {
+    public final func scheduleRelative<StateType>(_ state: StateType, dueTime: RxTimeInterval, action: @escaping @Sendable (StateType) -> Disposable) -> Disposable {
         self.configuration.scheduleRelative(state, dueTime: dueTime, action: action)
     }
     
@@ -125,7 +125,7 @@ public class SerialDispatchQueueScheduler : SchedulerType {
     - parameter action: Action to be executed.
     - returns: The disposable object used to cancel the scheduled action (best effort).
     */
-    public func schedulePeriodic<StateType>(_ state: StateType, startAfter: RxTimeInterval, period: RxTimeInterval, action: @escaping (StateType) -> StateType) -> Disposable {
+    public func schedulePeriodic<StateType>(_ state: StateType, startAfter: RxTimeInterval, period: RxTimeInterval, action: @escaping @Sendable (StateType) -> StateType) -> Disposable {
         self.configuration.schedulePeriodic(state, startAfter: startAfter, period: period, action: action)
     }
 }
diff --git a/RxSwift/Schedulers/VirtualTimeScheduler.swift b/RxSwift/Schedulers/VirtualTimeScheduler.swift
index 4f55d29d7..392513bfe 100644
--- a/RxSwift/Schedulers/VirtualTimeScheduler.swift
+++ b/RxSwift/Schedulers/VirtualTimeScheduler.swift
@@ -10,7 +10,8 @@ import Foundation
 
 /// Base class for virtual time schedulers using a priority queue for scheduled items.
 open class VirtualTimeScheduler<Converter: VirtualTimeConverterType>
-    : SchedulerType {
+    : SchedulerType
+    , @unchecked Sendable {
 
     public typealias VirtualTime = Converter.VirtualTimeUnit
     public typealias VirtualTimeInterval = Converter.VirtualTimeIntervalUnit
@@ -24,6 +25,8 @@ open class VirtualTimeScheduler<Converter: VirtualTimeConverterType>
 
     private var nextId = 0
 
+    private let thread: Thread
+
     /// - returns: Current time.
     public var now: RxTime {
         self.converter.convertFromVirtualTime(self.clock)
@@ -41,6 +44,7 @@ open class VirtualTimeScheduler<Converter: VirtualTimeConverterType>
         self.currentClock = initialClock
         self.running = false
         self.converter = converter
+        self.thread = Thread.current
         self.schedulerQueue = PriorityQueue(hasHigherPriority: {
             switch converter.compareVirtualTime($0.time, $1.time) {
             case .lessThan:
@@ -63,7 +67,7 @@ open class VirtualTimeScheduler<Converter: VirtualTimeConverterType>
     - parameter action: Action to be executed.
     - returns: The disposable object used to cancel the scheduled action (best effort).
     */
-    public func schedule<StateType>(_ state: StateType, action: @escaping (StateType) -> Disposable) -> Disposable {
+    public func schedule<StateType>(_ state: StateType, action: @escaping @Sendable (StateType) -> Disposable) -> Disposable {
         return self.scheduleRelative(state, dueTime: .microseconds(0)) { a in
             return action(a)
         }
@@ -77,7 +81,7 @@ open class VirtualTimeScheduler<Converter: VirtualTimeConverterType>
      - parameter action: Action to be executed.
      - returns: The disposable object used to cancel the scheduled action (best effort).
      */
-    public func scheduleRelative<StateType>(_ state: StateType, dueTime: RxTimeInterval, action: @escaping (StateType) -> Disposable) -> Disposable {
+    public func scheduleRelative<StateType>(_ state: StateType, dueTime: RxTimeInterval, action: @escaping @Sendable (StateType) -> Disposable) -> Disposable {
         let time = self.now.addingDispatchInterval(dueTime)
         let absoluteTime = self.converter.convertToVirtualTime(time)
         let adjustedTime = self.adjustScheduledTime(absoluteTime)
@@ -92,7 +96,7 @@ open class VirtualTimeScheduler<Converter: VirtualTimeConverterType>
      - parameter action: Action to be executed.
      - returns: The disposable object used to cancel the scheduled action (best effort).
      */
-    public func scheduleRelativeVirtual<StateType>(_ state: StateType, dueTime: VirtualTimeInterval, action: @escaping (StateType) -> Disposable) -> Disposable {
+    public func scheduleRelativeVirtual<StateType>(_ state: StateType, dueTime: VirtualTimeInterval, action: @escaping @Sendable (StateType) -> Disposable) -> Disposable {
         let time = self.converter.offsetVirtualTime(self.clock, offset: dueTime)
         return self.scheduleAbsoluteVirtual(state, time: time, action: action)
     }
@@ -105,9 +109,8 @@ open class VirtualTimeScheduler<Converter: VirtualTimeConverterType>
      - parameter action: Action to be executed.
      - returns: The disposable object used to cancel the scheduled action (best effort).
      */
-    public func scheduleAbsoluteVirtual<StateType>(_ state: StateType, time: VirtualTime, action: @escaping (StateType) -> Disposable) -> Disposable {
-        MainScheduler.ensureExecutingOnScheduler()
-
+    public func scheduleAbsoluteVirtual<StateType>(_ state: StateType, time: VirtualTime, action: @escaping @Sendable (StateType) -> Disposable) -> Disposable {
+        ensusreRunningOnCorrectThread()
         let compositeDisposable = CompositeDisposable()
 
         let item = VirtualSchedulerItem(action: {
@@ -130,12 +133,11 @@ open class VirtualTimeScheduler<Converter: VirtualTimeConverterType>
 
     /// Starts the virtual time scheduler.
     public func start() {
-        MainScheduler.ensureExecutingOnScheduler()
-
         if self.running {
             return
         }
 
+        ensusreRunningOnCorrectThread()
         self.running = true
         repeat {
             guard let next = self.findNext() else {
@@ -170,12 +172,11 @@ open class VirtualTimeScheduler<Converter: VirtualTimeConverterType>
     ///
     /// - parameter virtualTime: Absolute time to advance the scheduler's clock to.
     public func advanceTo(_ virtualTime: VirtualTime) {
-        MainScheduler.ensureExecutingOnScheduler()
-
         if self.running {
             fatalError("Scheduler is already running")
         }
 
+        ensusreRunningOnCorrectThread()
         self.running = true
         repeat {
             guard let next = self.findNext() else {
@@ -199,8 +200,7 @@ open class VirtualTimeScheduler<Converter: VirtualTimeConverterType>
 
     /// Advances the scheduler's clock by the specified relative time.
     public func sleep(_ virtualInterval: VirtualTimeInterval) {
-        MainScheduler.ensureExecutingOnScheduler()
-
+        ensusreRunningOnCorrectThread()
         let sleepTo = self.converter.offsetVirtualTime(self.clock, offset: virtualInterval)
         if self.converter.compareVirtualTime(sleepTo, self.clock).lessThen {
             fatalError("Can't sleep to past.")
@@ -211,8 +211,7 @@ open class VirtualTimeScheduler<Converter: VirtualTimeConverterType>
 
     /// Stops the virtual time scheduler.
     public func stop() {
-        MainScheduler.ensureExecutingOnScheduler()
-
+        ensusreRunningOnCorrectThread()
         self.running = false
     }
 
@@ -221,6 +220,12 @@ open class VirtualTimeScheduler<Converter: VirtualTimeConverterType>
             _ = Resources.decrementTotal()
         }
     #endif
+
+    private func ensusreRunningOnCorrectThread() {
+        guard Thread.current == thread else {
+            rxFatalError("Executing on the wrong thread. Please ensure all work on the same thread.")
+        }
+    }
 }
 
 // MARK: description
@@ -233,8 +238,9 @@ extension VirtualTimeScheduler: CustomDebugStringConvertible {
 }
 
 final class VirtualSchedulerItem<Time>
-    : Disposable {
-    typealias Action = () -> Disposable
+    : Disposable
+    , @unchecked Sendable {
+    typealias Action = @Sendable () -> Disposable
     
     let action: Action
     let time: Time
diff --git a/RxSwift/Subjects/AsyncSubject.swift b/RxSwift/Subjects/AsyncSubject.swift
index 30b012f0b..c23fa127d 100644
--- a/RxSwift/Subjects/AsyncSubject.swift
+++ b/RxSwift/Subjects/AsyncSubject.swift
@@ -14,7 +14,8 @@ public final class AsyncSubject<Element>
     : Observable<Element>
     , SubjectType
     , ObserverType
-    , SynchronizedUnsubscribeType {
+    , SynchronizedUnsubscribeType
+    , @unchecked Sendable {
     public typealias SubjectObserverType = AsyncSubject<Element>
 
     typealias Observers = AnyObserver<Element>.s
diff --git a/RxSwift/Subjects/BehaviorSubject.swift b/RxSwift/Subjects/BehaviorSubject.swift
index 7251f616b..ca2225b72 100644
--- a/RxSwift/Subjects/BehaviorSubject.swift
+++ b/RxSwift/Subjects/BehaviorSubject.swift
@@ -14,7 +14,8 @@ public final class BehaviorSubject<Element>
     , SubjectType
     , ObserverType
     , SynchronizedUnsubscribeType
-    , Cancelable {
+    , Cancelable
+    , @unchecked Sendable {
     public typealias SubjectObserverType = BehaviorSubject<Element>
 
     typealias Observers = AnyObserver<Element>.s
diff --git a/RxSwift/Subjects/PublishSubject.swift b/RxSwift/Subjects/PublishSubject.swift
index 0318486ef..74eefc590 100644
--- a/RxSwift/Subjects/PublishSubject.swift
+++ b/RxSwift/Subjects/PublishSubject.swift
@@ -14,7 +14,8 @@ public final class PublishSubject<Element>
     , SubjectType
     , Cancelable
     , ObserverType
-    , SynchronizedUnsubscribeType {
+    , SynchronizedUnsubscribeType
+    , @unchecked Sendable {
     public typealias SubjectObserverType = PublishSubject<Element>
 
     typealias Observers = AnyObserver<Element>.s
diff --git a/RxSwift/Subjects/ReplaySubject.swift b/RxSwift/Subjects/ReplaySubject.swift
index 2336ce78f..e45cd6d40 100644
--- a/RxSwift/Subjects/ReplaySubject.swift
+++ b/RxSwift/Subjects/ReplaySubject.swift
@@ -13,7 +13,8 @@ public class ReplaySubject<Element>
     : Observable<Element>
     , SubjectType
     , ObserverType
-    , Disposable {
+    , Disposable
+    , @unchecked Sendable {
     public typealias SubjectObserverType = ReplaySubject<Element>
 
     typealias Observers = AnyObserver<Element>.s
@@ -93,7 +94,8 @@ public class ReplaySubject<Element>
 
 private class ReplayBufferBase<Element>
     : ReplaySubject<Element>
-    , SynchronizedUnsubscribeType {
+    , SynchronizedUnsubscribeType
+    , @unchecked Sendable {
     
     func trim() {
         rxAbstractMethod()
@@ -190,7 +192,7 @@ private class ReplayBufferBase<Element>
     }
 }
 
-private final class ReplayOne<Element> : ReplayBufferBase<Element> {
+private final class ReplayOne<Element> : ReplayBufferBase<Element>, @unchecked Sendable {
     private var value: Element?
     
     override init() {
@@ -217,7 +219,7 @@ private final class ReplayOne<Element> : ReplayBufferBase<Element> {
     }
 }
 
-private class ReplayManyBase<Element>: ReplayBufferBase<Element> {
+private class ReplayManyBase<Element>: ReplayBufferBase<Element>, @unchecked Sendable {
     fileprivate var queue: Queue<Element>
     
     init(queueSize: Int) {
@@ -240,7 +242,7 @@ private class ReplayManyBase<Element>: ReplayBufferBase<Element> {
     }
 }
 
-private final class ReplayMany<Element> : ReplayManyBase<Element> {
+private final class ReplayMany<Element> : ReplayManyBase<Element>, @unchecked Sendable {
     private let bufferSize: Int
     
     init(bufferSize: Int) {
@@ -256,7 +258,7 @@ private final class ReplayMany<Element> : ReplayManyBase<Element> {
     }
 }
 
-private final class ReplayAll<Element> : ReplayManyBase<Element> {
+private final class ReplayAll<Element> : ReplayManyBase<Element>, @unchecked Sendable {
     init() {
         super.init(queueSize: 0)
     }
diff --git a/RxSwift/Traits/Infallible/Infallible+CombineLatest+Collection.swift b/RxSwift/Traits/Infallible/Infallible+CombineLatest+Collection.swift
index e0e66408c..c58e084cf 100644
--- a/RxSwift/Traits/Infallible/Infallible+CombineLatest+Collection.swift
+++ b/RxSwift/Traits/Infallible/Infallible+CombineLatest+Collection.swift
@@ -17,7 +17,7 @@ extension InfallibleType {
      - parameter resultSelector: Function to invoke whenever any of the sources produces an element.
      - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
      */
-    public static func combineLatest<Collection: Swift.Collection>(_ collection: Collection, resultSelector: @escaping ([Collection.Element.Element]) throws -> Element) -> Infallible<Element>
+    public static func combineLatest<Collection: Swift.Collection>(_ collection: Collection, resultSelector: @escaping @Sendable ([Collection.Element.Element]) throws -> Element) -> Infallible<Element>
         where Collection.Element: InfallibleType {
         Infallible(CombineLatestCollectionType(sources: collection, resultSelector: resultSelector))
     }
diff --git a/RxSwift/Traits/Infallible/Infallible+CombineLatest+arity.swift b/RxSwift/Traits/Infallible/Infallible+CombineLatest+arity.swift
index 4bcc7656f..4cb386edd 100644
--- a/RxSwift/Traits/Infallible/Infallible+CombineLatest+arity.swift
+++ b/RxSwift/Traits/Infallible/Infallible+CombineLatest+arity.swift
@@ -20,7 +20,7 @@ extension Infallible {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func combineLatest<I1: InfallibleType, I2: InfallibleType>
-        (_ source1: I1, _ source2: I2, resultSelector: @escaping (I1.Element, I2.Element) throws -> Element)
+    (_ source1: I1, _ source2: I2, resultSelector: @escaping @Sendable (I1.Element, I2.Element) throws -> Element)
             -> Infallible<Element> {
         Infallible(CombineLatest2(
             source1: source1.asObservable(), source2: source2.asObservable(),
@@ -58,7 +58,7 @@ extension Infallible {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func combineLatest<I1: InfallibleType, I2: InfallibleType, I3: InfallibleType>
-        (_ source1: I1, _ source2: I2, _ source3: I3, resultSelector: @escaping (I1.Element, I2.Element, I3.Element) throws -> Element)
+    (_ source1: I1, _ source2: I2, _ source3: I3, resultSelector: @escaping @Sendable (I1.Element, I2.Element, I3.Element) throws -> Element)
             -> Infallible<Element> {
         Infallible(CombineLatest3(
             source1: source1.asObservable(), source2: source2.asObservable(), source3: source3.asObservable(),
@@ -96,7 +96,7 @@ extension Infallible {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func combineLatest<I1: InfallibleType, I2: InfallibleType, I3: InfallibleType, I4: InfallibleType>
-        (_ source1: I1, _ source2: I2, _ source3: I3, _ source4: I4, resultSelector: @escaping (I1.Element, I2.Element, I3.Element, I4.Element) throws -> Element)
+    (_ source1: I1, _ source2: I2, _ source3: I3, _ source4: I4, resultSelector: @escaping @Sendable (I1.Element, I2.Element, I3.Element, I4.Element) throws -> Element)
             -> Infallible<Element> {
         Infallible(CombineLatest4(
             source1: source1.asObservable(), source2: source2.asObservable(), source3: source3.asObservable(), source4: source4.asObservable(),
@@ -134,7 +134,7 @@ extension Infallible {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func combineLatest<I1: InfallibleType, I2: InfallibleType, I3: InfallibleType, I4: InfallibleType, I5: InfallibleType>
-        (_ source1: I1, _ source2: I2, _ source3: I3, _ source4: I4, _ source5: I5, resultSelector: @escaping (I1.Element, I2.Element, I3.Element, I4.Element, I5.Element) throws -> Element)
+    (_ source1: I1, _ source2: I2, _ source3: I3, _ source4: I4, _ source5: I5, resultSelector: @escaping @Sendable (I1.Element, I2.Element, I3.Element, I4.Element, I5.Element) throws -> Element)
             -> Infallible<Element> {
         Infallible(CombineLatest5(
             source1: source1.asObservable(), source2: source2.asObservable(), source3: source3.asObservable(), source4: source4.asObservable(), source5: source5.asObservable(),
@@ -172,7 +172,7 @@ extension Infallible {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func combineLatest<I1: InfallibleType, I2: InfallibleType, I3: InfallibleType, I4: InfallibleType, I5: InfallibleType, I6: InfallibleType>
-        (_ source1: I1, _ source2: I2, _ source3: I3, _ source4: I4, _ source5: I5, _ source6: I6, resultSelector: @escaping (I1.Element, I2.Element, I3.Element, I4.Element, I5.Element, I6.Element) throws -> Element)
+    (_ source1: I1, _ source2: I2, _ source3: I3, _ source4: I4, _ source5: I5, _ source6: I6, resultSelector: @escaping @Sendable (I1.Element, I2.Element, I3.Element, I4.Element, I5.Element, I6.Element) throws -> Element)
             -> Infallible<Element> {
         Infallible(CombineLatest6(
             source1: source1.asObservable(), source2: source2.asObservable(), source3: source3.asObservable(), source4: source4.asObservable(), source5: source5.asObservable(), source6: source6.asObservable(),
@@ -210,7 +210,7 @@ extension Infallible {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func combineLatest<I1: InfallibleType, I2: InfallibleType, I3: InfallibleType, I4: InfallibleType, I5: InfallibleType, I6: InfallibleType, I7: InfallibleType>
-        (_ source1: I1, _ source2: I2, _ source3: I3, _ source4: I4, _ source5: I5, _ source6: I6, _ source7: I7, resultSelector: @escaping (I1.Element, I2.Element, I3.Element, I4.Element, I5.Element, I6.Element, I7.Element) throws -> Element)
+    (_ source1: I1, _ source2: I2, _ source3: I3, _ source4: I4, _ source5: I5, _ source6: I6, _ source7: I7, resultSelector: @escaping @Sendable (I1.Element, I2.Element, I3.Element, I4.Element, I5.Element, I6.Element, I7.Element) throws -> Element)
             -> Infallible<Element> {
         Infallible(CombineLatest7(
             source1: source1.asObservable(), source2: source2.asObservable(), source3: source3.asObservable(), source4: source4.asObservable(), source5: source5.asObservable(), source6: source6.asObservable(), source7: source7.asObservable(),
@@ -248,7 +248,7 @@ extension Infallible {
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
     public static func combineLatest<I1: InfallibleType, I2: InfallibleType, I3: InfallibleType, I4: InfallibleType, I5: InfallibleType, I6: InfallibleType, I7: InfallibleType, I8: InfallibleType>
-        (_ source1: I1, _ source2: I2, _ source3: I3, _ source4: I4, _ source5: I5, _ source6: I6, _ source7: I7, _ source8: I8, resultSelector: @escaping (I1.Element, I2.Element, I3.Element, I4.Element, I5.Element, I6.Element, I7.Element, I8.Element) throws -> Element)
+    (_ source1: I1, _ source2: I2, _ source3: I3, _ source4: I4, _ source5: I5, _ source6: I6, _ source7: I7, _ source8: I8, resultSelector: @escaping @Sendable (I1.Element, I2.Element, I3.Element, I4.Element, I5.Element, I6.Element, I7.Element, I8.Element) throws -> Element)
             -> Infallible<Element> {
         Infallible(CombineLatest8(
             source1: source1.asObservable(), source2: source2.asObservable(), source3: source3.asObservable(), source4: source4.asObservable(), source5: source5.asObservable(), source6: source6.asObservable(), source7: source7.asObservable(), source8: source8.asObservable(),
diff --git a/RxSwift/Traits/Infallible/Infallible+Create.swift b/RxSwift/Traits/Infallible/Infallible+Create.swift
index 8fb177170..a40076561 100644
--- a/RxSwift/Traits/Infallible/Infallible+Create.swift
+++ b/RxSwift/Traits/Infallible/Infallible+Create.swift
@@ -17,7 +17,7 @@ public enum InfallibleEvent<Element> {
 }
 
 extension Infallible {
-    public typealias InfallibleObserver = (InfallibleEvent<Element>) -> Void
+    public typealias InfallibleObserver = @Sendable (InfallibleEvent<Element>) -> Void
 
     /**
      Creates an observable sequence from a specified subscribe method implementation.
@@ -27,9 +27,9 @@ extension Infallible {
      - parameter subscribe: Implementation of the resulting observable sequence's `subscribe` method.
      - returns: The observable sequence with the specified implementation for the `subscribe` method.
      */
-    public static func create(subscribe: @escaping (@escaping InfallibleObserver) -> Disposable) -> Infallible<Element> {
-        let source = Observable<Element>.create { observer in
-            subscribe { event in
+    public static func create(subscribe: @escaping @Sendable (@escaping InfallibleObserver) -> Disposable) -> Infallible<Element> {
+        let source = Observable<Element>.create { @Sendable observer in
+            subscribe { @Sendable event in
                 switch event {
                 case .next(let element):
                     observer.onNext(element)
diff --git a/RxSwift/Traits/Infallible/Infallible+Operators.swift b/RxSwift/Traits/Infallible/Infallible+Operators.swift
index c9209f874..d970bc228 100644
--- a/RxSwift/Traits/Infallible/Infallible+Operators.swift
+++ b/RxSwift/Traits/Infallible/Infallible+Operators.swift
@@ -66,7 +66,7 @@ extension InfallibleType {
      - parameter observableFactory: Observable factory function to invoke for each observer that subscribes to the resulting sequence.
      - returns: An observable sequence whose observers trigger an invocation of the given observable factory function.
      */
-    public static func deferred(_ observableFactory: @escaping () throws -> Infallible<Element>)
+    public static func deferred(_ observableFactory: @escaping @Sendable () throws -> Infallible<Element>)
         -> Infallible<Element> {
         Infallible(.deferred { try observableFactory().asObservable() })
     }
@@ -123,7 +123,7 @@ extension InfallibleType {
      - parameter predicate: A function to test each source element for a condition.
      - returns: An observable sequence that contains elements from the input sequence that satisfy the condition.
      */
-    public func filter(_ predicate: @escaping (Element) -> Bool)
+    public func filter(_ predicate: @escaping @Sendable (Element) -> Bool)
         -> Infallible<Element> {
         Infallible(asObservable().filter(predicate))
     }
@@ -140,7 +140,7 @@ extension InfallibleType {
      - returns: An observable sequence whose elements are the result of invoking the transform function on each element of source.
 
      */
-    public func map<Result>(_ transform: @escaping (Element) -> Result)
+    public func map<Result>(_ transform: @escaping @Sendable (Element) -> Result)
         -> Infallible<Result> {
         Infallible(asObservable().map(transform))
     }
@@ -152,7 +152,7 @@ extension InfallibleType {
      - returns: An observable sequence whose elements are the result of filtering the transform function for each element of the source.
 
      */
-    public func compactMap<Result>(_ transform: @escaping (Element) -> Result?)
+    public func compactMap<Result>(_ transform: @escaping @Sendable (Element) -> Result?)
         -> Infallible<Result> {
         Infallible(asObservable().compactMap(transform))
     }
@@ -183,7 +183,7 @@ extension InfallibleType {
      - parameter keySelector: A function to compute the comparison key for each element.
      - returns: An observable sequence only containing the distinct contiguous elements, based on a computed key value, from the source sequence.
      */
-    public func distinctUntilChanged<Key: Equatable>(_ keySelector: @escaping (Element) throws -> Key)
+    public func distinctUntilChanged<Key: Equatable>(_ keySelector: @escaping @Sendable (Element) throws -> Key)
         -> Infallible<Element> {
         Infallible(self.asObservable().distinctUntilChanged(keySelector, comparer: { $0 == $1 }))
     }
@@ -196,7 +196,7 @@ extension InfallibleType {
      - parameter comparer: Equality comparer for computed key values.
      - returns: An observable sequence only containing the distinct contiguous elements, based on `comparer`, from the source sequence.
      */
-    public func distinctUntilChanged(_ comparer: @escaping (Element, Element) throws -> Bool)
+    public func distinctUntilChanged(_ comparer: @escaping @Sendable (Element, Element) throws -> Bool)
         -> Infallible<Element> {
         Infallible(self.asObservable().distinctUntilChanged({ $0 }, comparer: comparer))
     }
@@ -210,7 +210,7 @@ extension InfallibleType {
      - parameter comparer: Equality comparer for computed key values.
      - returns: An observable sequence only containing the distinct contiguous elements, based on a computed key value and the comparer, from the source sequence.
      */
-    public func distinctUntilChanged<K>(_ keySelector: @escaping (Element) throws -> K, comparer: @escaping (K, K) throws -> Bool)
+    public func distinctUntilChanged<K>(_ keySelector: @escaping @Sendable (Element) throws -> K, comparer: @escaping @Sendable (K, K) throws -> Bool)
         -> Infallible<Element> {
         Infallible(asObservable().distinctUntilChanged(keySelector, comparer: comparer))
     }
@@ -272,7 +272,7 @@ extension InfallibleType {
      - parameter selector: A transform function to apply to each element.
      - returns: An observable sequence whose elements are the result of invoking the one-to-many transform function on each element of the input sequence.
      */
-    public func flatMap<Source: ObservableConvertibleType>(_ selector: @escaping (Element) -> Source)
+    public func flatMap<Source: ObservableConvertibleType>(_ selector: @escaping @Sendable (Element) -> Source)
         -> Infallible<Source.Element> {
         Infallible(asObservable().flatMap(selector))
     }
@@ -289,7 +289,7 @@ extension InfallibleType {
      - returns: An observable sequence whose elements are the result of invoking the transform function on each element of source producing an
      Observable of Observable sequences and that at any point in time produces the elements of the most recent inner observable sequence that has been received.
      */
-    public func flatMapLatest<Source: ObservableConvertibleType>(_ selector: @escaping (Element) -> Source)
+    public func flatMapLatest<Source: ObservableConvertibleType>(_ selector: @escaping @Sendable (Element) -> Source)
         -> Infallible<Source.Element> {
         Infallible(asObservable().flatMapLatest(selector))
     }
@@ -303,7 +303,7 @@ extension InfallibleType {
      - parameter selector: A transform function to apply to element that was observed while no observable is executing in parallel.
      - returns: An observable sequence whose elements are the result of invoking the one-to-many transform function on each element of the input sequence that was received while no other sequence was being calculated.
      */
-    public func flatMapFirst<Source: ObservableConvertibleType>(_ selector: @escaping (Element) -> Source)
+    public func flatMapFirst<Source: ObservableConvertibleType>(_ selector: @escaping @Sendable (Element) -> Source)
         -> Infallible<Source.Element> {
         Infallible(asObservable().flatMapFirst(selector))
     }
@@ -383,7 +383,7 @@ extension InfallibleType {
 
      - returns: An observable sequence that contains the elements of each observed inner sequence, in sequential order.
      */
-    public func concatMap<Source: ObservableConvertibleType>(_ selector: @escaping (Element) -> Source)
+    public func concatMap<Source: ObservableConvertibleType>(_ selector: @escaping @Sendable (Element) -> Source)
         -> Infallible<Source.Element> {
         Infallible(asObservable().concatMap(selector))
     }
@@ -445,7 +445,7 @@ extension Infallible {
      - parameter onDispose: Action to invoke after subscription to source observable has been disposed for any reason. It can be either because sequence terminates for some reason or observer subscription being disposed.
      - returns: The source sequence with the side-effecting behavior applied.
      */
-    public func `do`(onNext: ((Element) throws -> Void)? = nil, afterNext: ((Element) throws -> Void)? = nil, onCompleted: (() throws -> Void)? = nil, afterCompleted: (() throws -> Void)? = nil, onSubscribe: (() -> Void)? = nil, onSubscribed: (() -> Void)? = nil, onDispose: (() -> Void)? = nil) -> Infallible<Element> {
+    public func `do`(onNext: (@Sendable (Element) throws -> Void)? = nil, afterNext: (@Sendable (Element) throws -> Void)? = nil, onCompleted: (@Sendable () throws -> Void)? = nil, afterCompleted: (@Sendable () throws -> Void)? = nil, onSubscribe: (@Sendable () -> Void)? = nil, onSubscribed: (@Sendable () -> Void)? = nil, onDispose: (@Sendable () -> Void)? = nil) -> Infallible<Element> {
         Infallible(asObservable().do(onNext: onNext, afterNext: afterNext, onCompleted: onCompleted, afterCompleted: afterCompleted, onSubscribe: onSubscribe, onSubscribed: onSubscribed, onDispose: onDispose))
     }
 }
@@ -463,7 +463,7 @@ extension InfallibleType {
      - parameter accumulator: An accumulator function to be invoked on each element.
      - returns: An observable sequence containing the accumulated values.
      */
-    public func scan<Seed>(into seed: Seed, accumulator: @escaping (inout Seed, Element) -> Void)
+    public func scan<Seed>(into seed: Seed, accumulator: @escaping @Sendable (inout Seed, Element) -> Void)
         -> Infallible<Seed> {
         Infallible(asObservable().scan(into: seed, accumulator: accumulator))
     }
@@ -479,7 +479,7 @@ extension InfallibleType {
      - parameter accumulator: An accumulator function to be invoked on each element.
      - returns: An observable sequence containing the accumulated values.
      */
-    public func scan<Seed>(_ seed: Seed, accumulator: @escaping (Seed, Element) -> Seed)
+    public func scan<Seed>(_ seed: Seed, accumulator: @escaping @Sendable (Seed, Element) -> Seed)
         -> Infallible<Seed> {
         Infallible(asObservable().scan(seed, accumulator: accumulator))
     }
@@ -541,7 +541,7 @@ extension InfallibleType {
 
      - returns: An observable sequence that contains the elements from the input sequence that occur before the element at which the test passes.
      */
-    public func take(until predicate: @escaping (Element) throws -> Bool,
+    public func take(until predicate: @escaping @Sendable (Element) throws -> Bool,
                      behavior: TakeBehavior = .exclusive)
         -> Infallible<Element> {
         Infallible(asObservable().take(until: predicate, behavior: behavior))
@@ -555,7 +555,7 @@ extension InfallibleType {
      - parameter predicate: A function to test each element for a condition.
      - returns: An observable sequence that contains the elements from the input sequence that occur before the element at which the test no longer passes.
      */
-    public func take(while predicate: @escaping (Element) throws -> Bool,
+    public func take(while predicate: @escaping @Sendable (Element) throws -> Bool,
                      behavior: TakeBehavior = .exclusive)
         -> Infallible<Element> {
         Infallible(asObservable().take(while: predicate, behavior: behavior))
@@ -595,7 +595,7 @@ extension InfallibleType {
      - parameter predicate: A function to test each element for a condition.
      - returns: An infallible sequence that contains the elements from the input sequence starting at the first element in the linear series that does not pass the test specified by predicate.
      */
-    public func skip(while predicate: @escaping (Element) throws -> Bool) -> Infallible<Element> {
+    public func skip(while predicate: @escaping @Sendable (Element) throws -> Bool) -> Infallible<Element> {
         Infallible(asObservable().skip(while: predicate))
     }
 
@@ -662,7 +662,7 @@ extension InfallibleType {
      */
     public func withUnretained<Object: AnyObject, Out>(
         _ obj: Object,
-        resultSelector: @escaping (Object, Element) -> Out
+        resultSelector: @escaping @Sendable (Object, Element) -> Out
     ) -> Infallible<Out> {
         Infallible(self.asObservable().withUnretained(obj, resultSelector: resultSelector))
     }
@@ -694,7 +694,7 @@ extension InfallibleType {
      - parameter resultSelector: Function to invoke for each element from the self combined with the latest element from the second source, if any.
      - returns: An observable sequence containing the result of combining each element of the self  with the latest element from the second source, if any, using the specified result selector function.
      */
-    public func withLatestFrom<Source: InfallibleType, ResultType>(_ second: Source, resultSelector: @escaping (Element, Source.Element) throws -> ResultType) -> Infallible<ResultType> {
+    public func withLatestFrom<Source: InfallibleType, ResultType>(_ second: Source, resultSelector: @escaping @Sendable (Element, Source.Element) throws -> ResultType) -> Infallible<ResultType> {
         Infallible(self.asObservable().withLatestFrom(second.asObservable(), resultSelector: resultSelector))
     }
 
diff --git a/RxSwift/Traits/Infallible/Infallible+Zip+arity.swift b/RxSwift/Traits/Infallible/Infallible+Zip+arity.swift
index 02eb4f641..635db42df 100644
--- a/RxSwift/Traits/Infallible/Infallible+Zip+arity.swift
+++ b/RxSwift/Traits/Infallible/Infallible+Zip+arity.swift
@@ -20,7 +20,7 @@ extension InfallibleType {
     - parameter resultSelector: Function to invoke for each series of elements at corresponding indexes in the sources.
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
-    public static func zip<E1, E2>(_ source1: Infallible<E1>, _ source2: Infallible<E2>, resultSelector: @escaping (E1, E2) throws -> Element)
+    public static func zip<E1, E2>(_ source1: Infallible<E1>, _ source2: Infallible<E2>, resultSelector: @escaping @Sendable (E1, E2) throws -> Element)
         -> Infallible<Element> {
         Infallible(
             Observable.zip(source1.asObservable(), source2.asObservable(), resultSelector: resultSelector)
@@ -38,7 +38,7 @@ extension InfallibleType {
     - parameter resultSelector: Function to invoke for each series of elements at corresponding indexes in the sources.
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
-    public static func zip<E1, E2, E3>(_ source1: Infallible<E1>, _ source2: Infallible<E2>, _ source3: Infallible<E3>, resultSelector: @escaping (E1, E2, E3) throws -> Element)
+    public static func zip<E1, E2, E3>(_ source1: Infallible<E1>, _ source2: Infallible<E2>, _ source3: Infallible<E3>, resultSelector: @escaping @Sendable (E1, E2, E3) throws -> Element)
         -> Infallible<Element> {
         Infallible(
             Observable.zip(source1.asObservable(), source2.asObservable(), source3.asObservable(), resultSelector: resultSelector)
@@ -56,7 +56,7 @@ extension InfallibleType {
     - parameter resultSelector: Function to invoke for each series of elements at corresponding indexes in the sources.
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
-    public static func zip<E1, E2, E3, E4>(_ source1: Infallible<E1>, _ source2: Infallible<E2>, _ source3: Infallible<E3>, _ source4: Infallible<E4>, resultSelector: @escaping (E1, E2, E3, E4) throws -> Element)
+    public static func zip<E1, E2, E3, E4>(_ source1: Infallible<E1>, _ source2: Infallible<E2>, _ source3: Infallible<E3>, _ source4: Infallible<E4>, resultSelector: @escaping @Sendable (E1, E2, E3, E4) throws -> Element)
         -> Infallible<Element> {
         Infallible(
             Observable.zip(source1.asObservable(), source2.asObservable(), source3.asObservable(), source4.asObservable(), resultSelector: resultSelector)
@@ -74,7 +74,7 @@ extension InfallibleType {
     - parameter resultSelector: Function to invoke for each series of elements at corresponding indexes in the sources.
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
-    public static func zip<E1, E2, E3, E4, E5>(_ source1: Infallible<E1>, _ source2: Infallible<E2>, _ source3: Infallible<E3>, _ source4: Infallible<E4>, _ source5: Infallible<E5>, resultSelector: @escaping (E1, E2, E3, E4, E5) throws -> Element)
+    public static func zip<E1, E2, E3, E4, E5>(_ source1: Infallible<E1>, _ source2: Infallible<E2>, _ source3: Infallible<E3>, _ source4: Infallible<E4>, _ source5: Infallible<E5>, resultSelector: @escaping @Sendable (E1, E2, E3, E4, E5) throws -> Element)
         -> Infallible<Element> {
         Infallible(
             Observable.zip(source1.asObservable(), source2.asObservable(), source3.asObservable(), source4.asObservable(), source5.asObservable(), resultSelector: resultSelector)
@@ -92,7 +92,7 @@ extension InfallibleType {
     - parameter resultSelector: Function to invoke for each series of elements at corresponding indexes in the sources.
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
-    public static func zip<E1, E2, E3, E4, E5, E6>(_ source1: Infallible<E1>, _ source2: Infallible<E2>, _ source3: Infallible<E3>, _ source4: Infallible<E4>, _ source5: Infallible<E5>, _ source6: Infallible<E6>, resultSelector: @escaping (E1, E2, E3, E4, E5, E6) throws -> Element)
+    public static func zip<E1, E2, E3, E4, E5, E6>(_ source1: Infallible<E1>, _ source2: Infallible<E2>, _ source3: Infallible<E3>, _ source4: Infallible<E4>, _ source5: Infallible<E5>, _ source6: Infallible<E6>, resultSelector: @escaping @Sendable (E1, E2, E3, E4, E5, E6) throws -> Element)
         -> Infallible<Element> {
         Infallible(
             Observable.zip(source1.asObservable(), source2.asObservable(), source3.asObservable(), source4.asObservable(), source5.asObservable(), source6.asObservable(), resultSelector: resultSelector)
@@ -110,7 +110,7 @@ extension InfallibleType {
     - parameter resultSelector: Function to invoke for each series of elements at corresponding indexes in the sources.
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
-    public static func zip<E1, E2, E3, E4, E5, E6, E7>(_ source1: Infallible<E1>, _ source2: Infallible<E2>, _ source3: Infallible<E3>, _ source4: Infallible<E4>, _ source5: Infallible<E5>, _ source6: Infallible<E6>, _ source7: Infallible<E7>, resultSelector: @escaping (E1, E2, E3, E4, E5, E6, E7) throws -> Element)
+    public static func zip<E1, E2, E3, E4, E5, E6, E7>(_ source1: Infallible<E1>, _ source2: Infallible<E2>, _ source3: Infallible<E3>, _ source4: Infallible<E4>, _ source5: Infallible<E5>, _ source6: Infallible<E6>, _ source7: Infallible<E7>, resultSelector: @escaping @Sendable (E1, E2, E3, E4, E5, E6, E7) throws -> Element)
         -> Infallible<Element> {
         Infallible(
             Observable.zip(source1.asObservable(), source2.asObservable(), source3.asObservable(), source4.asObservable(), source5.asObservable(), source6.asObservable(), source7.asObservable(), resultSelector: resultSelector)
@@ -128,7 +128,7 @@ extension InfallibleType {
     - parameter resultSelector: Function to invoke for each series of elements at corresponding indexes in the sources.
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
-    public static func zip<E1, E2, E3, E4, E5, E6, E7, E8>(_ source1: Infallible<E1>, _ source2: Infallible<E2>, _ source3: Infallible<E3>, _ source4: Infallible<E4>, _ source5: Infallible<E5>, _ source6: Infallible<E6>, _ source7: Infallible<E7>, _ source8: Infallible<E8>, resultSelector: @escaping (E1, E2, E3, E4, E5, E6, E7, E8) throws -> Element)
+    public static func zip<E1, E2, E3, E4, E5, E6, E7, E8>(_ source1: Infallible<E1>, _ source2: Infallible<E2>, _ source3: Infallible<E3>, _ source4: Infallible<E4>, _ source5: Infallible<E5>, _ source6: Infallible<E6>, _ source7: Infallible<E7>, _ source8: Infallible<E8>, resultSelector: @escaping @Sendable (E1, E2, E3, E4, E5, E6, E7, E8) throws -> Element)
         -> Infallible<Element> {
         Infallible(
             Observable.zip(source1.asObservable(), source2.asObservable(), source3.asObservable(), source4.asObservable(), source5.asObservable(), source6.asObservable(), source7.asObservable(), source8.asObservable(), resultSelector: resultSelector)
diff --git a/RxSwift/Traits/Infallible/Infallible.swift b/RxSwift/Traits/Infallible/Infallible.swift
index d5b5826a6..5d21d1276 100644
--- a/RxSwift/Traits/Infallible/Infallible.swift
+++ b/RxSwift/Traits/Infallible/Infallible.swift
@@ -48,9 +48,9 @@ extension InfallibleType {
      */
     public func subscribe<Object: AnyObject>(
         with object: Object,
-        onNext: ((Object, Element) -> Void)? = nil,
-        onCompleted: ((Object) -> Void)? = nil,
-        onDisposed: ((Object) -> Void)? = nil
+        onNext: (@Sendable (Object, Element) -> Void)? = nil,
+        onCompleted: (@Sendable (Object) -> Void)? = nil,
+        onDisposed: (@Sendable (Object) -> Void)? = nil
     ) -> Disposable {
         self.asObservable().subscribe(
             with: object,
@@ -72,9 +72,9 @@ extension InfallibleType {
      gracefully completed, errored, or if the generation is canceled by disposing subscription)
      - returns: Subscription object used to unsubscribe from the observable sequence.
     */
-    public func subscribe(onNext: ((Element) -> Void)? = nil,
-                          onCompleted: (() -> Void)? = nil,
-                          onDisposed: (() -> Void)? = nil) -> Disposable {
+    public func subscribe(onNext: (@Sendable (Element) -> Void)? = nil,
+                          onCompleted: (@Sendable () -> Void)? = nil,
+                          onDisposed: (@Sendable () -> Void)? = nil) -> Disposable {
         self.asObservable().subscribe(onNext: onNext,
                                       onCompleted: onCompleted,
                                       onDisposed: onDisposed)
@@ -86,8 +86,8 @@ extension InfallibleType {
      - parameter on: Action to invoke for each event in the observable sequence.
      - returns: Subscription object used to unsubscribe from the observable sequence.
      */
-    public func subscribe(_ on: @escaping (InfallibleEvent<Element>) -> Void) -> Disposable {
-        let eventHandler: ((Event<Element>) -> Void) = { event in
+    public func subscribe(_ on: @escaping @Sendable (InfallibleEvent<Element>) -> Void) -> Disposable {
+        let eventHandler: (@Sendable (Event<Element>) -> Void) = { event in
             switch event {
             case .next(let element):
                 on(.next(element))
diff --git a/RxSwift/Traits/Infallible/ObservableConvertibleType+Infallible.swift b/RxSwift/Traits/Infallible/ObservableConvertibleType+Infallible.swift
index d0f111c94..a84bad631 100644
--- a/RxSwift/Traits/Infallible/ObservableConvertibleType+Infallible.swift
+++ b/RxSwift/Traits/Infallible/ObservableConvertibleType+Infallible.swift
@@ -29,7 +29,7 @@ public extension ObservableConvertibleType {
     /// - parameter onErrorRecover: Recover with the this infallible closure
     ///
     /// - returns: `Infallible<Element>`
-    func asInfallible(onErrorRecover: @escaping (Swift.Error) -> Infallible<Element>) -> Infallible<Element> {
+    func asInfallible(onErrorRecover: @escaping @Sendable (Swift.Error) -> Infallible<Element>) -> Infallible<Element> {
         Infallible(asObservable().catch { onErrorRecover($0).asObservable() })
     }
 }
diff --git a/RxSwift/Traits/PrimitiveSequence/Completable+AndThen.swift b/RxSwift/Traits/PrimitiveSequence/Completable+AndThen.swift
index dd1dc9723..07967cf75 100644
--- a/RxSwift/Traits/PrimitiveSequence/Completable+AndThen.swift
+++ b/RxSwift/Traits/PrimitiveSequence/Completable+AndThen.swift
@@ -60,7 +60,7 @@ extension PrimitiveSequenceType where Trait == CompletableTrait, Element == Neve
     }
 }
 
-final private class ConcatCompletable<Element>: Producer<Element> {
+final private class ConcatCompletable<Element>: Producer<Element>, @unchecked Sendable {
     fileprivate let completable: Observable<Never>
     fileprivate let second: Observable<Element>
 
@@ -78,7 +78,8 @@ final private class ConcatCompletable<Element>: Producer<Element> {
 
 final private class ConcatCompletableSink<Observer: ObserverType>
     : Sink<Observer>
-    , ObserverType {
+    , ObserverType
+    , @unchecked Sendable {
     typealias Element = Never
     typealias Parent = ConcatCompletable<Observer.Element>
 
diff --git a/RxSwift/Traits/PrimitiveSequence/Completable.swift b/RxSwift/Traits/PrimitiveSequence/Completable.swift
index 1bca0ffa4..79ded312b 100644
--- a/RxSwift/Traits/PrimitiveSequence/Completable.swift
+++ b/RxSwift/Traits/PrimitiveSequence/Completable.swift
@@ -24,7 +24,7 @@ public typealias Completable = PrimitiveSequence<CompletableTrait, Swift.Never>
 }
 
 extension PrimitiveSequenceType where Trait == CompletableTrait, Element == Swift.Never {
-    public typealias CompletableObserver = (CompletableEvent) -> Void
+    public typealias CompletableObserver = @Sendable (CompletableEvent) -> Void
     
     /**
      Creates an observable sequence from a specified subscribe method implementation.
@@ -34,7 +34,7 @@ extension PrimitiveSequenceType where Trait == CompletableTrait, Element == Swif
      - parameter subscribe: Implementation of the resulting observable sequence's `subscribe` method.
      - returns: The observable sequence with the specified implementation for the `subscribe` method.
      */
-    public static func create(subscribe: @escaping (@escaping CompletableObserver) -> Disposable) -> PrimitiveSequence<Trait, Element> {
+    public static func create(subscribe: @escaping @Sendable (@escaping @Sendable CompletableObserver) -> Disposable) -> PrimitiveSequence<Trait, Element> {
         let source = Observable<Element>.create { observer in
             return subscribe { event in
                 switch event {
@@ -54,8 +54,8 @@ extension PrimitiveSequenceType where Trait == CompletableTrait, Element == Swif
      
      - returns: Subscription for `observer` that can be used to cancel production of sequence elements and free resources.
      */
-    public func subscribe(_ observer: @escaping (CompletableEvent) -> Void) -> Disposable {
-        var stopped = false
+    public func subscribe(_ observer: @escaping @Sendable (CompletableEvent) -> Void) -> Disposable {
+        nonisolated(unsafe) var stopped = false
         return self.primitiveSequence.asObservable().subscribe { event in
             if stopped { return }
             stopped = true
@@ -87,9 +87,9 @@ extension PrimitiveSequenceType where Trait == CompletableTrait, Element == Swif
      */
     public func subscribe<Object: AnyObject>(
         with object: Object,
-        onCompleted: ((Object) -> Void)? = nil,
-        onError: ((Object, Swift.Error) -> Void)? = nil,
-        onDisposed: ((Object) -> Void)? = nil
+        onCompleted: (@Sendable (Object) -> Void)? = nil,
+        onError: (@Sendable (Object, Swift.Error) -> Void)? = nil,
+        onDisposed: (@Sendable (Object) -> Void)? = nil
     ) -> Disposable {
         subscribe(
             onCompleted: { [weak object] in
@@ -114,9 +114,9 @@ extension PrimitiveSequenceType where Trait == CompletableTrait, Element == Swif
      gracefully completed, errored, or if the generation is canceled by disposing subscription).
      - returns: Subscription object used to unsubscribe from the observable sequence.
      */
-    public func subscribe(onCompleted: (() -> Void)? = nil,
-                          onError: ((Swift.Error) -> Void)? = nil,
-                          onDisposed: (() -> Void)? = nil) -> Disposable {
+    public func subscribe(onCompleted: (@Sendable () -> Void)? = nil,
+                          onError: (@Sendable (Swift.Error) -> Void)? = nil,
+                          onDisposed: (@Sendable () -> Void)? = nil) -> Disposable {
         #if DEBUG
                 let callStack = Hooks.recordCallStackOnError ? Thread.callStackSymbols : []
         #else
@@ -199,13 +199,13 @@ extension PrimitiveSequenceType where Trait == CompletableTrait, Element == Swif
      - parameter onDispose: Action to invoke after subscription to source observable has been disposed for any reason. It can be either because sequence terminates for some reason or observer subscription being disposed.
      - returns: The source sequence with the side-effecting behavior applied.
      */
-    public func `do`(onError: ((Swift.Error) throws -> Void)? = nil,
-                     afterError: ((Swift.Error) throws -> Void)? = nil,
-                     onCompleted: (() throws -> Void)? = nil,
-                     afterCompleted: (() throws -> Void)? = nil,
-                     onSubscribe: (() -> Void)? = nil,
-                     onSubscribed: (() -> Void)? = nil,
-                     onDispose: (() -> Void)? = nil)
+    public func `do`(onError: (@Sendable (Swift.Error) throws -> Void)? = nil,
+                     afterError: (@Sendable (Swift.Error) throws -> Void)? = nil,
+                     onCompleted: (@Sendable () throws -> Void)? = nil,
+                     afterCompleted: (@Sendable () throws -> Void)? = nil,
+                     onSubscribe: (@Sendable () -> Void)? = nil,
+                     onSubscribed: (@Sendable () -> Void)? = nil,
+                     onDispose: (@Sendable () -> Void)? = nil)
         -> Completable {
             return Completable(raw: self.primitiveSequence.source.do(
                 onError: onError,
diff --git a/RxSwift/Traits/PrimitiveSequence/Maybe.swift b/RxSwift/Traits/PrimitiveSequence/Maybe.swift
index d73048fb3..eac57e0b1 100644
--- a/RxSwift/Traits/PrimitiveSequence/Maybe.swift
+++ b/RxSwift/Traits/PrimitiveSequence/Maybe.swift
@@ -27,7 +27,7 @@ public typealias Maybe<Element> = PrimitiveSequence<MaybeTrait, Element>
 }
 
 extension PrimitiveSequenceType where Trait == MaybeTrait {
-    public typealias MaybeObserver = (MaybeEvent<Element>) -> Void
+    public typealias MaybeObserver = @Sendable (MaybeEvent<Element>) -> Void
     
     /**
      Creates an observable sequence from a specified subscribe method implementation.
@@ -37,7 +37,7 @@ extension PrimitiveSequenceType where Trait == MaybeTrait {
      - parameter subscribe: Implementation of the resulting observable sequence's `subscribe` method.
      - returns: The observable sequence with the specified implementation for the `subscribe` method.
      */
-    public static func create(subscribe: @escaping (@escaping MaybeObserver) -> Disposable) -> PrimitiveSequence<Trait, Element> {
+    public static func create(subscribe: @escaping @Sendable (@escaping MaybeObserver) -> Disposable) -> PrimitiveSequence<Trait, Element> {
         let source = Observable<Element>.create { observer in
             return subscribe { event in
                 switch event {
@@ -60,8 +60,8 @@ extension PrimitiveSequenceType where Trait == MaybeTrait {
      
      - returns: Subscription for `observer` that can be used to cancel production of sequence elements and free resources.
      */
-    public func subscribe(_ observer: @escaping (MaybeEvent<Element>) -> Void) -> Disposable {
-        var stopped = false
+    public func subscribe(_ observer: @escaping @Sendable (MaybeEvent<Element>) -> Void) -> Disposable {
+        nonisolated(unsafe) var stopped = false
         return self.primitiveSequence.asObservable().subscribe { event in
             if stopped { return }
             stopped = true
@@ -94,10 +94,10 @@ extension PrimitiveSequenceType where Trait == MaybeTrait {
      */
     public func subscribe<Object: AnyObject>(
         with object: Object,
-        onSuccess: ((Object, Element) -> Void)? = nil,
-        onError: ((Object, Swift.Error) -> Void)? = nil,
-        onCompleted: ((Object) -> Void)? = nil,
-        onDisposed: ((Object) -> Void)? = nil
+        onSuccess: (@Sendable (Object, Element) -> Void)? = nil,
+        onError: (@Sendable (Object, Swift.Error) -> Void)? = nil,
+        onCompleted: (@Sendable (Object) -> Void)? = nil,
+        onDisposed: (@Sendable (Object) -> Void)? = nil
     ) -> Disposable {
         subscribe(
             onSuccess: { [weak object] in
@@ -129,10 +129,10 @@ extension PrimitiveSequenceType where Trait == MaybeTrait {
      gracefully completed, errored, or if the generation is canceled by disposing subscription).
      - returns: Subscription object used to unsubscribe from the observable sequence.
      */
-    public func subscribe(onSuccess: ((Element) -> Void)? = nil,
-                          onError: ((Swift.Error) -> Void)? = nil,
-                          onCompleted: (() -> Void)? = nil,
-                          onDisposed: (() -> Void)? = nil) -> Disposable {
+    public func subscribe(onSuccess: (@Sendable (Element) -> Void)? = nil,
+                          onError: (@Sendable (Swift.Error) -> Void)? = nil,
+                          onCompleted: (@Sendable () -> Void)? = nil,
+                          onDisposed: (@Sendable () -> Void)? = nil) -> Disposable {
         #if DEBUG
             let callStack = Hooks.recordCallStackOnError ? Thread.callStackSymbols : []
         #else
@@ -242,15 +242,15 @@ extension PrimitiveSequenceType where Trait == MaybeTrait {
      - parameter onDispose: Action to invoke after subscription to source observable has been disposed for any reason. It can be either because sequence terminates for some reason or observer subscription being disposed.
      - returns: The source sequence with the side-effecting behavior applied.
      */
-    public func `do`(onNext: ((Element) throws -> Void)? = nil,
-                     afterNext: ((Element) throws -> Void)? = nil,
-                     onError: ((Swift.Error) throws -> Void)? = nil,
-                     afterError: ((Swift.Error) throws -> Void)? = nil,
-                     onCompleted: (() throws -> Void)? = nil,
-                     afterCompleted: (() throws -> Void)? = nil,
-                     onSubscribe: (() -> Void)? = nil,
-                     onSubscribed: (() -> Void)? = nil,
-                     onDispose: (() -> Void)? = nil)
+    public func `do`(onNext: (@Sendable (Element) throws -> Void)? = nil,
+                     afterNext: (@Sendable (Element) throws -> Void)? = nil,
+                     onError: (@Sendable (Swift.Error) throws -> Void)? = nil,
+                     afterError: (@Sendable (Swift.Error) throws -> Void)? = nil,
+                     onCompleted: (@Sendable () throws -> Void)? = nil,
+                     afterCompleted: (@Sendable () throws -> Void)? = nil,
+                     onSubscribe: (@Sendable () -> Void)? = nil,
+                     onSubscribed: (@Sendable () -> Void)? = nil,
+                     onDispose: (@Sendable () -> Void)? = nil)
         -> Maybe<Element> {
             return Maybe(raw: self.primitiveSequence.source.do(
                 onNext: onNext,
@@ -273,7 +273,7 @@ extension PrimitiveSequenceType where Trait == MaybeTrait {
      - parameter predicate: A function to test each source element for a condition.
      - returns: An observable sequence that contains elements from the input sequence that satisfy the condition.
      */
-    public func filter(_ predicate: @escaping (Element) throws -> Bool)
+    public func filter(_ predicate: @escaping @Sendable (Element) throws -> Bool)
         -> Maybe<Element> {
             return Maybe(raw: self.primitiveSequence.source.filter(predicate))
     }
@@ -287,7 +287,7 @@ extension PrimitiveSequenceType where Trait == MaybeTrait {
      - returns: An observable sequence whose elements are the result of invoking the transform function on each element of source.
      
      */
-    public func map<Result>(_ transform: @escaping (Element) throws -> Result)
+    public func map<Result>(_ transform: @escaping @Sendable (Element) throws -> Result)
         -> Maybe<Result> {
             return Maybe(raw: self.primitiveSequence.source.map(transform))
     }
@@ -299,7 +299,7 @@ extension PrimitiveSequenceType where Trait == MaybeTrait {
      - returns: An observable sequence whose elements are the result of filtering the transform function for each element of the source.
      
      */
-    public func compactMap<Result>(_ transform: @escaping (Element) throws -> Result?)
+    public func compactMap<Result>(_ transform: @escaping @Sendable (Element) throws -> Result?)
         -> Maybe<Result> {
         Maybe(raw: self.primitiveSequence.source.compactMap(transform))
     }
@@ -312,7 +312,7 @@ extension PrimitiveSequenceType where Trait == MaybeTrait {
      - parameter selector: A transform function to apply to each element.
      - returns: An observable sequence whose elements are the result of invoking the one-to-many transform function on each element of the input sequence.
      */
-    public func flatMap<Result>(_ selector: @escaping (Element) throws -> Maybe<Result>)
+    public func flatMap<Result>(_ selector: @escaping @Sendable (Element) throws -> Maybe<Result>)
         -> Maybe<Result> {
             return Maybe<Result>(raw: self.primitiveSequence.source.flatMap(selector))
     }
diff --git a/RxSwift/Traits/PrimitiveSequence/PrimitiveSequence+Concurrency.swift b/RxSwift/Traits/PrimitiveSequence/PrimitiveSequence+Concurrency.swift
index 68b816b8b..6453ffc5a 100644
--- a/RxSwift/Traits/PrimitiveSequence/PrimitiveSequence+Concurrency.swift
+++ b/RxSwift/Traits/PrimitiveSequence/PrimitiveSequence+Concurrency.swift
@@ -24,7 +24,7 @@ public extension PrimitiveSequenceType where Trait == SingleTrait {
     static func create(
         detached: Bool = false,
         priority: TaskPriority? = nil,
-        work: @Sendable @escaping () async throws -> Element
+        work: @escaping @Sendable () async throws -> Element
     ) -> PrimitiveSequence<Trait, Element> {
         .create { single in
             let operation: () async throws -> Void = {
@@ -61,7 +61,7 @@ public extension PrimitiveSequenceType where Trait == SingleTrait {
             return try await withTaskCancellationHandler(
                 operation: {
                     try await withCheckedThrowingContinuation { continuation in
-                        var didResume = false
+                        nonisolated(unsafe) var didResume = false
                         disposable.setDisposable(
                             self.subscribe(
                                 onSuccess: {
@@ -111,8 +111,8 @@ public extension PrimitiveSequenceType where Trait == MaybeTrait {
             return try await withTaskCancellationHandler(
                 operation: {
                     try await withCheckedThrowingContinuation { continuation in
-                        var didEmit = false
-                        var didResume = false
+                        nonisolated(unsafe) var didEmit = false
+                        nonisolated(unsafe) var didResume = false
                         disposable.setDisposable(
                             self.subscribe(
                                 onSuccess: { value in
@@ -167,7 +167,7 @@ public extension PrimitiveSequenceType where Trait == CompletableTrait, Element
             return try await withTaskCancellationHandler(
                 operation: {
                     try await withCheckedThrowingContinuation { continuation in
-                        var didResume = false
+                        nonisolated(unsafe) var didResume = false
                         disposable.setDisposable(
                             self.subscribe(
                                 onCompleted: {
diff --git a/RxSwift/Traits/PrimitiveSequence/PrimitiveSequence+Zip+arity.swift b/RxSwift/Traits/PrimitiveSequence/PrimitiveSequence+Zip+arity.swift
index 80a6928f4..3c903b325 100644
--- a/RxSwift/Traits/PrimitiveSequence/PrimitiveSequence+Zip+arity.swift
+++ b/RxSwift/Traits/PrimitiveSequence/PrimitiveSequence+Zip+arity.swift
@@ -20,7 +20,7 @@ extension PrimitiveSequenceType where Trait == SingleTrait {
     - parameter resultSelector: Function to invoke for each series of elements at corresponding indexes in the sources.
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
-    public static func zip<E1, E2>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, resultSelector: @escaping (E1, E2) throws -> Element)
+    public static func zip<E1, E2>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, resultSelector: @escaping @Sendable (E1, E2) throws -> Element)
         -> PrimitiveSequence<Trait, Element> {
             return PrimitiveSequence(raw: Observable.zip(
             source1.asObservable(), source2.asObservable(),
@@ -54,7 +54,7 @@ extension PrimitiveSequenceType where Trait == MaybeTrait {
     - parameter resultSelector: Function to invoke for each series of elements at corresponding indexes in the sources.
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
-    public static func zip<E1, E2>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, resultSelector: @escaping (E1, E2) throws -> Element)
+    public static func zip<E1, E2>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, resultSelector: @escaping @Sendable (E1, E2) throws -> Element)
         -> PrimitiveSequence<Trait, Element> {
             return PrimitiveSequence(raw: Observable.zip(
             source1.asObservable(), source2.asObservable(),
@@ -93,7 +93,7 @@ extension PrimitiveSequenceType where Trait == SingleTrait {
     - parameter resultSelector: Function to invoke for each series of elements at corresponding indexes in the sources.
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
-    public static func zip<E1, E2, E3>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, _ source3: PrimitiveSequence<Trait, E3>, resultSelector: @escaping (E1, E2, E3) throws -> Element)
+    public static func zip<E1, E2, E3>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, _ source3: PrimitiveSequence<Trait, E3>, resultSelector: @escaping @Sendable (E1, E2, E3) throws -> Element)
         -> PrimitiveSequence<Trait, Element> {
             return PrimitiveSequence(raw: Observable.zip(
             source1.asObservable(), source2.asObservable(), source3.asObservable(),
@@ -127,7 +127,7 @@ extension PrimitiveSequenceType where Trait == MaybeTrait {
     - parameter resultSelector: Function to invoke for each series of elements at corresponding indexes in the sources.
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
-    public static func zip<E1, E2, E3>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, _ source3: PrimitiveSequence<Trait, E3>, resultSelector: @escaping (E1, E2, E3) throws -> Element)
+    public static func zip<E1, E2, E3>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, _ source3: PrimitiveSequence<Trait, E3>, resultSelector: @escaping @Sendable (E1, E2, E3) throws -> Element)
         -> PrimitiveSequence<Trait, Element> {
             return PrimitiveSequence(raw: Observable.zip(
             source1.asObservable(), source2.asObservable(), source3.asObservable(),
@@ -166,7 +166,7 @@ extension PrimitiveSequenceType where Trait == SingleTrait {
     - parameter resultSelector: Function to invoke for each series of elements at corresponding indexes in the sources.
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
-    public static func zip<E1, E2, E3, E4>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, _ source3: PrimitiveSequence<Trait, E3>, _ source4: PrimitiveSequence<Trait, E4>, resultSelector: @escaping (E1, E2, E3, E4) throws -> Element)
+    public static func zip<E1, E2, E3, E4>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, _ source3: PrimitiveSequence<Trait, E3>, _ source4: PrimitiveSequence<Trait, E4>, resultSelector: @escaping @Sendable (E1, E2, E3, E4) throws -> Element)
         -> PrimitiveSequence<Trait, Element> {
             return PrimitiveSequence(raw: Observable.zip(
             source1.asObservable(), source2.asObservable(), source3.asObservable(), source4.asObservable(),
@@ -200,7 +200,7 @@ extension PrimitiveSequenceType where Trait == MaybeTrait {
     - parameter resultSelector: Function to invoke for each series of elements at corresponding indexes in the sources.
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
-    public static func zip<E1, E2, E3, E4>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, _ source3: PrimitiveSequence<Trait, E3>, _ source4: PrimitiveSequence<Trait, E4>, resultSelector: @escaping (E1, E2, E3, E4) throws -> Element)
+    public static func zip<E1, E2, E3, E4>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, _ source3: PrimitiveSequence<Trait, E3>, _ source4: PrimitiveSequence<Trait, E4>, resultSelector: @escaping @Sendable (E1, E2, E3, E4) throws -> Element)
         -> PrimitiveSequence<Trait, Element> {
             return PrimitiveSequence(raw: Observable.zip(
             source1.asObservable(), source2.asObservable(), source3.asObservable(), source4.asObservable(),
@@ -239,7 +239,7 @@ extension PrimitiveSequenceType where Trait == SingleTrait {
     - parameter resultSelector: Function to invoke for each series of elements at corresponding indexes in the sources.
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
-    public static func zip<E1, E2, E3, E4, E5>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, _ source3: PrimitiveSequence<Trait, E3>, _ source4: PrimitiveSequence<Trait, E4>, _ source5: PrimitiveSequence<Trait, E5>, resultSelector: @escaping (E1, E2, E3, E4, E5) throws -> Element)
+    public static func zip<E1, E2, E3, E4, E5>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, _ source3: PrimitiveSequence<Trait, E3>, _ source4: PrimitiveSequence<Trait, E4>, _ source5: PrimitiveSequence<Trait, E5>, resultSelector: @escaping @Sendable (E1, E2, E3, E4, E5) throws -> Element)
         -> PrimitiveSequence<Trait, Element> {
             return PrimitiveSequence(raw: Observable.zip(
             source1.asObservable(), source2.asObservable(), source3.asObservable(), source4.asObservable(), source5.asObservable(),
@@ -273,7 +273,7 @@ extension PrimitiveSequenceType where Trait == MaybeTrait {
     - parameter resultSelector: Function to invoke for each series of elements at corresponding indexes in the sources.
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
-    public static func zip<E1, E2, E3, E4, E5>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, _ source3: PrimitiveSequence<Trait, E3>, _ source4: PrimitiveSequence<Trait, E4>, _ source5: PrimitiveSequence<Trait, E5>, resultSelector: @escaping (E1, E2, E3, E4, E5) throws -> Element)
+    public static func zip<E1, E2, E3, E4, E5>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, _ source3: PrimitiveSequence<Trait, E3>, _ source4: PrimitiveSequence<Trait, E4>, _ source5: PrimitiveSequence<Trait, E5>, resultSelector: @escaping @Sendable (E1, E2, E3, E4, E5) throws -> Element)
         -> PrimitiveSequence<Trait, Element> {
             return PrimitiveSequence(raw: Observable.zip(
             source1.asObservable(), source2.asObservable(), source3.asObservable(), source4.asObservable(), source5.asObservable(),
@@ -312,7 +312,7 @@ extension PrimitiveSequenceType where Trait == SingleTrait {
     - parameter resultSelector: Function to invoke for each series of elements at corresponding indexes in the sources.
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
-    public static func zip<E1, E2, E3, E4, E5, E6>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, _ source3: PrimitiveSequence<Trait, E3>, _ source4: PrimitiveSequence<Trait, E4>, _ source5: PrimitiveSequence<Trait, E5>, _ source6: PrimitiveSequence<Trait, E6>, resultSelector: @escaping (E1, E2, E3, E4, E5, E6) throws -> Element)
+    public static func zip<E1, E2, E3, E4, E5, E6>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, _ source3: PrimitiveSequence<Trait, E3>, _ source4: PrimitiveSequence<Trait, E4>, _ source5: PrimitiveSequence<Trait, E5>, _ source6: PrimitiveSequence<Trait, E6>, resultSelector: @escaping @Sendable (E1, E2, E3, E4, E5, E6) throws -> Element)
         -> PrimitiveSequence<Trait, Element> {
             return PrimitiveSequence(raw: Observable.zip(
             source1.asObservable(), source2.asObservable(), source3.asObservable(), source4.asObservable(), source5.asObservable(), source6.asObservable(),
@@ -346,7 +346,7 @@ extension PrimitiveSequenceType where Trait == MaybeTrait {
     - parameter resultSelector: Function to invoke for each series of elements at corresponding indexes in the sources.
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
-    public static func zip<E1, E2, E3, E4, E5, E6>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, _ source3: PrimitiveSequence<Trait, E3>, _ source4: PrimitiveSequence<Trait, E4>, _ source5: PrimitiveSequence<Trait, E5>, _ source6: PrimitiveSequence<Trait, E6>, resultSelector: @escaping (E1, E2, E3, E4, E5, E6) throws -> Element)
+    public static func zip<E1, E2, E3, E4, E5, E6>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, _ source3: PrimitiveSequence<Trait, E3>, _ source4: PrimitiveSequence<Trait, E4>, _ source5: PrimitiveSequence<Trait, E5>, _ source6: PrimitiveSequence<Trait, E6>, resultSelector: @escaping @Sendable (E1, E2, E3, E4, E5, E6) throws -> Element)
         -> PrimitiveSequence<Trait, Element> {
             return PrimitiveSequence(raw: Observable.zip(
             source1.asObservable(), source2.asObservable(), source3.asObservable(), source4.asObservable(), source5.asObservable(), source6.asObservable(),
@@ -385,7 +385,7 @@ extension PrimitiveSequenceType where Trait == SingleTrait {
     - parameter resultSelector: Function to invoke for each series of elements at corresponding indexes in the sources.
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
-    public static func zip<E1, E2, E3, E4, E5, E6, E7>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, _ source3: PrimitiveSequence<Trait, E3>, _ source4: PrimitiveSequence<Trait, E4>, _ source5: PrimitiveSequence<Trait, E5>, _ source6: PrimitiveSequence<Trait, E6>, _ source7: PrimitiveSequence<Trait, E7>, resultSelector: @escaping (E1, E2, E3, E4, E5, E6, E7) throws -> Element)
+    public static func zip<E1, E2, E3, E4, E5, E6, E7>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, _ source3: PrimitiveSequence<Trait, E3>, _ source4: PrimitiveSequence<Trait, E4>, _ source5: PrimitiveSequence<Trait, E5>, _ source6: PrimitiveSequence<Trait, E6>, _ source7: PrimitiveSequence<Trait, E7>, resultSelector: @escaping @Sendable (E1, E2, E3, E4, E5, E6, E7) throws -> Element)
         -> PrimitiveSequence<Trait, Element> {
             return PrimitiveSequence(raw: Observable.zip(
             source1.asObservable(), source2.asObservable(), source3.asObservable(), source4.asObservable(), source5.asObservable(), source6.asObservable(), source7.asObservable(),
@@ -419,7 +419,7 @@ extension PrimitiveSequenceType where Trait == MaybeTrait {
     - parameter resultSelector: Function to invoke for each series of elements at corresponding indexes in the sources.
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
-    public static func zip<E1, E2, E3, E4, E5, E6, E7>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, _ source3: PrimitiveSequence<Trait, E3>, _ source4: PrimitiveSequence<Trait, E4>, _ source5: PrimitiveSequence<Trait, E5>, _ source6: PrimitiveSequence<Trait, E6>, _ source7: PrimitiveSequence<Trait, E7>, resultSelector: @escaping (E1, E2, E3, E4, E5, E6, E7) throws -> Element)
+    public static func zip<E1, E2, E3, E4, E5, E6, E7>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, _ source3: PrimitiveSequence<Trait, E3>, _ source4: PrimitiveSequence<Trait, E4>, _ source5: PrimitiveSequence<Trait, E5>, _ source6: PrimitiveSequence<Trait, E6>, _ source7: PrimitiveSequence<Trait, E7>, resultSelector: @escaping @Sendable (E1, E2, E3, E4, E5, E6, E7) throws -> Element)
         -> PrimitiveSequence<Trait, Element> {
             return PrimitiveSequence(raw: Observable.zip(
             source1.asObservable(), source2.asObservable(), source3.asObservable(), source4.asObservable(), source5.asObservable(), source6.asObservable(), source7.asObservable(),
@@ -458,7 +458,7 @@ extension PrimitiveSequenceType where Trait == SingleTrait {
     - parameter resultSelector: Function to invoke for each series of elements at corresponding indexes in the sources.
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
-    public static func zip<E1, E2, E3, E4, E5, E6, E7, E8>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, _ source3: PrimitiveSequence<Trait, E3>, _ source4: PrimitiveSequence<Trait, E4>, _ source5: PrimitiveSequence<Trait, E5>, _ source6: PrimitiveSequence<Trait, E6>, _ source7: PrimitiveSequence<Trait, E7>, _ source8: PrimitiveSequence<Trait, E8>, resultSelector: @escaping (E1, E2, E3, E4, E5, E6, E7, E8) throws -> Element)
+    public static func zip<E1, E2, E3, E4, E5, E6, E7, E8>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, _ source3: PrimitiveSequence<Trait, E3>, _ source4: PrimitiveSequence<Trait, E4>, _ source5: PrimitiveSequence<Trait, E5>, _ source6: PrimitiveSequence<Trait, E6>, _ source7: PrimitiveSequence<Trait, E7>, _ source8: PrimitiveSequence<Trait, E8>, resultSelector: @escaping @Sendable (E1, E2, E3, E4, E5, E6, E7, E8) throws -> Element)
         -> PrimitiveSequence<Trait, Element> {
             return PrimitiveSequence(raw: Observable.zip(
             source1.asObservable(), source2.asObservable(), source3.asObservable(), source4.asObservable(), source5.asObservable(), source6.asObservable(), source7.asObservable(), source8.asObservable(),
@@ -492,7 +492,7 @@ extension PrimitiveSequenceType where Trait == MaybeTrait {
     - parameter resultSelector: Function to invoke for each series of elements at corresponding indexes in the sources.
     - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
     */
-    public static func zip<E1, E2, E3, E4, E5, E6, E7, E8>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, _ source3: PrimitiveSequence<Trait, E3>, _ source4: PrimitiveSequence<Trait, E4>, _ source5: PrimitiveSequence<Trait, E5>, _ source6: PrimitiveSequence<Trait, E6>, _ source7: PrimitiveSequence<Trait, E7>, _ source8: PrimitiveSequence<Trait, E8>, resultSelector: @escaping (E1, E2, E3, E4, E5, E6, E7, E8) throws -> Element)
+    public static func zip<E1, E2, E3, E4, E5, E6, E7, E8>(_ source1: PrimitiveSequence<Trait, E1>, _ source2: PrimitiveSequence<Trait, E2>, _ source3: PrimitiveSequence<Trait, E3>, _ source4: PrimitiveSequence<Trait, E4>, _ source5: PrimitiveSequence<Trait, E5>, _ source6: PrimitiveSequence<Trait, E6>, _ source7: PrimitiveSequence<Trait, E7>, _ source8: PrimitiveSequence<Trait, E8>, resultSelector: @escaping @Sendable (E1, E2, E3, E4, E5, E6, E7, E8) throws -> Element)
         -> PrimitiveSequence<Trait, Element> {
             return PrimitiveSequence(raw: Observable.zip(
             source1.asObservable(), source2.asObservable(), source3.asObservable(), source4.asObservable(), source5.asObservable(), source6.asObservable(), source7.asObservable(), source8.asObservable(),
diff --git a/RxSwift/Traits/PrimitiveSequence/PrimitiveSequence.swift b/RxSwift/Traits/PrimitiveSequence/PrimitiveSequence.swift
index 04733d5a4..8bbd7a4bf 100644
--- a/RxSwift/Traits/PrimitiveSequence/PrimitiveSequence.swift
+++ b/RxSwift/Traits/PrimitiveSequence/PrimitiveSequence.swift
@@ -58,7 +58,7 @@ extension PrimitiveSequence {
      - parameter observableFactory: Observable factory function to invoke for each observer that subscribes to the resulting sequence.
      - returns: An observable sequence whose observers trigger an invocation of the given observable factory function.
      */
-    public static func deferred(_ observableFactory: @escaping () throws -> PrimitiveSequence<Trait, Element>)
+    public static func deferred(_ observableFactory: @escaping @Sendable () throws -> PrimitiveSequence<Trait, Element>)
         -> PrimitiveSequence<Trait, Element> {
         return PrimitiveSequence(raw: Observable.deferred {
             try observableFactory().asObservable()
@@ -176,7 +176,7 @@ extension PrimitiveSequence {
      - returns: An observable sequence containing the source sequence's elements, followed by the elements produced by the handler's resulting observable sequence in case an error occurred.
      */
     @available(*, deprecated, renamed: "catch(_:)")
-    public func catchError(_ handler: @escaping (Swift.Error) throws -> PrimitiveSequence<Trait, Element>)
+    public func catchError(_ handler: @escaping @Sendable (Swift.Error) throws -> PrimitiveSequence<Trait, Element>)
         -> PrimitiveSequence<Trait, Element> {
         `catch`(handler)
     }
@@ -189,7 +189,7 @@ extension PrimitiveSequence {
      - parameter handler: Error handler function, producing another observable sequence.
      - returns: An observable sequence containing the source sequence's elements, followed by the elements produced by the handler's resulting observable sequence in case an error occurred.
      */
-    public func `catch`(_ handler: @escaping (Swift.Error) throws -> PrimitiveSequence<Trait, Element>)
+    public func `catch`(_ handler: @escaping @Sendable (Swift.Error) throws -> PrimitiveSequence<Trait, Element>)
         -> PrimitiveSequence<Trait, Element> {
         PrimitiveSequence(raw: self.source.catch { try handler($0).asObservable() })
     }
@@ -216,7 +216,7 @@ extension PrimitiveSequence {
      - parameter notificationHandler: A handler that is passed an observable sequence of errors raised by the source observable and returns and observable that either continues, completes or errors. This behavior is then applied to the source observable.
      - returns: An observable sequence producing the elements of the given sequence repeatedly until it terminates successfully or is notified to error or complete.
      */
-    public func retry<TriggerObservable: ObservableType, Error: Swift.Error>(when notificationHandler: @escaping (Observable<Error>) -> TriggerObservable)
+    public func retry<TriggerObservable: ObservableType, Error: Swift.Error>(when notificationHandler: @escaping @Sendable (Observable<Error>) -> TriggerObservable)
         -> PrimitiveSequence<Trait, Element> {
         PrimitiveSequence(raw: self.source.retry(when: notificationHandler))
     }
@@ -231,7 +231,7 @@ extension PrimitiveSequence {
      - returns: An observable sequence producing the elements of the given sequence repeatedly until it terminates successfully or is notified to error or complete.
      */
     @available(*, deprecated, renamed: "retry(when:)")
-    public func retryWhen<TriggerObservable: ObservableType, Error: Swift.Error>(_ notificationHandler: @escaping (Observable<Error>) -> TriggerObservable)
+    public func retryWhen<TriggerObservable: ObservableType, Error: Swift.Error>(_ notificationHandler: @escaping @Sendable (Observable<Error>) -> TriggerObservable)
         -> PrimitiveSequence<Trait, Element> {
         retry(when: notificationHandler)
     }
@@ -245,7 +245,7 @@ extension PrimitiveSequence {
      - parameter notificationHandler: A handler that is passed an observable sequence of errors raised by the source observable and returns and observable that either continues, completes or errors. This behavior is then applied to the source observable.
      - returns: An observable sequence producing the elements of the given sequence repeatedly until it terminates successfully or is notified to error or complete.
      */
-    public func retry<TriggerObservable: ObservableType>(when notificationHandler: @escaping (Observable<Swift.Error>) -> TriggerObservable)
+    public func retry<TriggerObservable: ObservableType>(when notificationHandler: @escaping @Sendable (Observable<Swift.Error>) -> TriggerObservable)
         -> PrimitiveSequence<Trait, Element> {
         PrimitiveSequence(raw: self.source.retry(when: notificationHandler))
     }
@@ -260,7 +260,7 @@ extension PrimitiveSequence {
      - returns: An observable sequence producing the elements of the given sequence repeatedly until it terminates successfully or is notified to error or complete.
      */
     @available(*, deprecated, renamed: "retry(when:)")
-    public func retryWhen<TriggerObservable: ObservableType>(_ notificationHandler: @escaping (Observable<Swift.Error>) -> TriggerObservable)
+    public func retryWhen<TriggerObservable: ObservableType>(_ notificationHandler: @escaping @Sendable (Observable<Swift.Error>) -> TriggerObservable)
         -> PrimitiveSequence<Trait, Element> {
         retry(when: notificationHandler)
     }
@@ -288,7 +288,7 @@ extension PrimitiveSequence {
      - parameter primitiveSequenceFactory: Factory function to obtain an observable sequence that depends on the obtained resource.
      - returns: An observable sequence whose lifetime controls the lifetime of the dependent resource object.
      */
-    public static func using<Resource: Disposable>(_ resourceFactory: @escaping () throws -> Resource, primitiveSequenceFactory: @escaping (Resource) throws -> PrimitiveSequence<Trait, Element>)
+    public static func using<Resource: Disposable>(_ resourceFactory: @escaping @Sendable () throws -> Resource, primitiveSequenceFactory: @escaping @Sendable (Resource) throws -> PrimitiveSequence<Trait, Element>)
         -> PrimitiveSequence<Trait, Element> {
         PrimitiveSequence(raw: Observable.using(resourceFactory, observableFactory: { (resource: Resource) throws -> Observable<Element> in
             return try primitiveSequenceFactory(resource).asObservable()
diff --git a/RxSwift/Traits/PrimitiveSequence/Single.swift b/RxSwift/Traits/PrimitiveSequence/Single.swift
index 79595d175..e3906d622 100644
--- a/RxSwift/Traits/PrimitiveSequence/Single.swift
+++ b/RxSwift/Traits/PrimitiveSequence/Single.swift
@@ -17,7 +17,7 @@ public typealias Single<Element> = PrimitiveSequence<SingleTrait, Element>
 public typealias SingleEvent<Element> = Result<Element, Swift.Error>
 
 extension PrimitiveSequenceType where Trait == SingleTrait {
-    public typealias SingleObserver = (SingleEvent<Element>) -> Void
+    public typealias SingleObserver = @Sendable (SingleEvent<Element>) -> Void
     
     /**
      Creates an observable sequence from a specified subscribe method implementation.
@@ -27,7 +27,7 @@ extension PrimitiveSequenceType where Trait == SingleTrait {
      - parameter subscribe: Implementation of the resulting observable sequence's `subscribe` method.
      - returns: The observable sequence with the specified implementation for the `subscribe` method.
      */
-    public static func create(subscribe: @escaping (@escaping SingleObserver) -> Disposable) -> Single<Element> {
+    public static func create(subscribe: @escaping @Sendable (@escaping @Sendable SingleObserver) -> Disposable) -> Single<Element> {
         let source = Observable<Element>.create { observer in
             return subscribe { event in
                 switch event {
@@ -48,8 +48,8 @@ extension PrimitiveSequenceType where Trait == SingleTrait {
      
      - returns: Subscription for `observer` that can be used to cancel production of sequence elements and free resources.
      */
-    public func subscribe(_ observer: @escaping (SingleEvent<Element>) -> Void) -> Disposable {
-        var stopped = false
+    public func subscribe(_ observer: @escaping @Sendable (SingleEvent<Element>) -> Void) -> Disposable {
+        nonisolated(unsafe) var stopped = false
         return self.primitiveSequence.asObservable().subscribe { event in
             if stopped { return }
             stopped = true
@@ -75,9 +75,9 @@ extension PrimitiveSequenceType where Trait == SingleTrait {
      - returns: Subscription object used to unsubscribe from the observable sequence.
      */
     @available(*, deprecated, renamed: "subscribe(onSuccess:onFailure:onDisposed:)")
-    public func subscribe(onSuccess: ((Element) -> Void)? = nil,
-                          onError: @escaping ((Swift.Error) -> Void),
-                          onDisposed: (() -> Void)? = nil) -> Disposable {
+    public func subscribe(onSuccess: (@Sendable (Element) -> Void)? = nil,
+                          onError: @escaping (@Sendable (Swift.Error) -> Void),
+                          onDisposed: (@Sendable () -> Void)? = nil) -> Disposable {
         subscribe(onSuccess: onSuccess, onFailure: onError, onDisposed: onDisposed)
     }
     
@@ -97,9 +97,9 @@ extension PrimitiveSequenceType where Trait == SingleTrait {
      */
     public func subscribe<Object: AnyObject>(
         with object: Object,
-        onSuccess: ((Object, Element) -> Void)? = nil,
-        onFailure: ((Object, Swift.Error) -> Void)? = nil,
-        onDisposed: ((Object) -> Void)? = nil
+        onSuccess: (@Sendable (Object, Element) -> Void)? = nil,
+        onFailure: (@Sendable (Object, Swift.Error) -> Void)? = nil,
+        onDisposed: (@Sendable (Object) -> Void)? = nil
     ) -> Disposable {
         subscribe(
             onSuccess: { [weak object] in
@@ -126,9 +126,9 @@ extension PrimitiveSequenceType where Trait == SingleTrait {
      gracefully completed, errored, or if the generation is canceled by disposing subscription).
      - returns: Subscription object used to unsubscribe from the observable sequence.
      */
-    public func subscribe(onSuccess: ((Element) -> Void)? = nil,
-                          onFailure: ((Swift.Error) -> Void)? = nil,
-                          onDisposed: (() -> Void)? = nil) -> Disposable {
+    public func subscribe(onSuccess: (@Sendable (Element) -> Void)? = nil,
+                          onFailure: (@Sendable (Swift.Error) -> Void)? = nil,
+                          onDisposed: (@Sendable () -> Void)? = nil) -> Disposable {
         #if DEBUG
             let callStack = Hooks.recordCallStackOnError ? Thread.callStackSymbols : []
         #else
@@ -224,13 +224,13 @@ extension PrimitiveSequenceType where Trait == SingleTrait {
      - parameter onDispose: Action to invoke after subscription to source observable has been disposed for any reason. It can be either because sequence terminates for some reason or observer subscription being disposed.
      - returns: The source sequence with the side-effecting behavior applied.
      */
-    public func `do`(onSuccess: ((Element) throws -> Void)? = nil,
-                     afterSuccess: ((Element) throws -> Void)? = nil,
-                     onError: ((Swift.Error) throws -> Void)? = nil,
-                     afterError: ((Swift.Error) throws -> Void)? = nil,
-                     onSubscribe: (() -> Void)? = nil,
-                     onSubscribed: (() -> Void)? = nil,
-                     onDispose: (() -> Void)? = nil)
+    public func `do`(onSuccess: (@Sendable (Element) throws -> Void)? = nil,
+                     afterSuccess: (@Sendable (Element) throws -> Void)? = nil,
+                     onError: (@Sendable (Swift.Error) throws -> Void)? = nil,
+                     afterError: (@Sendable (Swift.Error) throws -> Void)? = nil,
+                     onSubscribe: (@Sendable () -> Void)? = nil,
+                     onSubscribed: (@Sendable () -> Void)? = nil,
+                     onDispose: (@Sendable () -> Void)? = nil)
         -> Single<Element> {
             return Single(raw: self.primitiveSequence.source.do(
                 onNext: onSuccess,
@@ -251,7 +251,7 @@ extension PrimitiveSequenceType where Trait == SingleTrait {
      - parameter predicate: A function to test each source element for a condition.
      - returns: An observable sequence that contains elements from the input sequence that satisfy the condition.
      */
-    public func filter(_ predicate: @escaping (Element) throws -> Bool)
+    public func filter(_ predicate: @escaping @Sendable (Element) throws -> Bool)
         -> Maybe<Element> {
             return Maybe(raw: self.primitiveSequence.source.filter(predicate))
     }
@@ -265,7 +265,7 @@ extension PrimitiveSequenceType where Trait == SingleTrait {
      - returns: An observable sequence whose elements are the result of invoking the transform function on each element of source.
      
      */
-    public func map<Result>(_ transform: @escaping (Element) throws -> Result)
+    public func map<Result>(_ transform: @escaping @Sendable (Element) throws -> Result)
         -> Single<Result> {
             return Single(raw: self.primitiveSequence.source.map(transform))
     }
@@ -277,7 +277,7 @@ extension PrimitiveSequenceType where Trait == SingleTrait {
      - returns: An observable sequence whose elements are the result of filtering the transform function for each element of the source.
 
      */
-    public func compactMap<Result>(_ transform: @escaping (Element) throws -> Result?)
+    public func compactMap<Result>(_ transform: @escaping @Sendable (Element) throws -> Result?)
         -> Maybe<Result> {
         Maybe(raw: self.primitiveSequence.source.compactMap(transform))
     }
@@ -290,7 +290,7 @@ extension PrimitiveSequenceType where Trait == SingleTrait {
      - parameter selector: A transform function to apply to each element.
      - returns: An observable sequence whose elements are the result of invoking the one-to-many transform function on each element of the input sequence.
      */
-    public func flatMap<Result>(_ selector: @escaping (Element) throws -> Single<Result>)
+    public func flatMap<Result>(_ selector: @escaping @Sendable (Element) throws -> Single<Result>)
         -> Single<Result> {
             return Single<Result>(raw: self.primitiveSequence.source.flatMap(selector))
     }
@@ -303,7 +303,7 @@ extension PrimitiveSequenceType where Trait == SingleTrait {
      - parameter selector: A transform function to apply to each element.
      - returns: An observable sequence whose elements are the result of invoking the one-to-many transform function on each element of the input sequence.
      */
-    public func flatMapMaybe<Result>(_ selector: @escaping (Element) throws -> Maybe<Result>)
+    public func flatMapMaybe<Result>(_ selector: @escaping @Sendable (Element) throws -> Maybe<Result>)
         -> Maybe<Result> {
             return Maybe<Result>(raw: self.primitiveSequence.source.flatMap(selector))
     }
@@ -316,7 +316,7 @@ extension PrimitiveSequenceType where Trait == SingleTrait {
      - parameter selector: A transform function to apply to each element.
      - returns: An observable sequence whose elements are the result of invoking the one-to-many transform function on each element of the input sequence.
      */
-    public func flatMapCompletable(_ selector: @escaping (Element) throws -> Completable)
+    public func flatMapCompletable(_ selector: @escaping @Sendable (Element) throws -> Completable)
         -> Completable {
             return Completable(raw: self.primitiveSequence.source.flatMap(selector))
     }
@@ -327,7 +327,7 @@ extension PrimitiveSequenceType where Trait == SingleTrait {
      - parameter resultSelector: Function to invoke for each series of elements at corresponding indexes in the sources.
      - returns: An observable sequence containing the result of combining elements of the sources using the specified result selector function.
      */
-    public static func zip<Collection: Swift.Collection, Result>(_ collection: Collection, resultSelector: @escaping ([Element]) throws -> Result) -> PrimitiveSequence<Trait, Result> where Collection.Element == PrimitiveSequence<Trait, Element> {
+    public static func zip<Collection: Swift.Collection, Result>(_ collection: Collection, resultSelector: @escaping @Sendable ([Element]) throws -> Result) -> PrimitiveSequence<Trait, Result> where Collection.Element == PrimitiveSequence<Trait, Element> {
         
         if collection.isEmpty {
             return PrimitiveSequence<Trait, Result>.deferred {
diff --git a/RxTest/Schedulers/TestScheduler.swift b/RxTest/Schedulers/TestScheduler.swift
index af15d1fee..4ec3ce05f 100644
--- a/RxTest/Schedulers/TestScheduler.swift
+++ b/RxTest/Schedulers/TestScheduler.swift
@@ -70,7 +70,7 @@ public class TestScheduler : VirtualTimeScheduler<TestSchedulerVirtualTimeConver
 
      - parameter time: Absolute virtual time at which to execute the action.
      */
-    public func scheduleAt(_ time: TestTime, action: @escaping () -> Void) {
+    public func scheduleAt(_ time: TestTime, action: @escaping @Sendable () -> Void) {
         _ = self.scheduleAbsoluteVirtual((), time: time, action: { _ -> Disposable in
             action()
             return Disposables.create()
@@ -93,10 +93,10 @@ public class TestScheduler : VirtualTimeScheduler<TestSchedulerVirtualTimeConver
     - parameter create: Factory method to create an observable convertible sequence.
     - returns: Observer with timestamped recordings of events that were received during the virtual time window when the subscription to the source sequence was active.
     */
-    public func start<Element, OutputSequence: ObservableConvertibleType>(created: TestTime, subscribed: TestTime, disposed: TestTime, create: @escaping () -> OutputSequence)
+    public func start<Element, OutputSequence: ObservableConvertibleType>(created: TestTime, subscribed: TestTime, disposed: TestTime, create: @escaping @Sendable () -> OutputSequence)
         -> TestableObserver<Element> where OutputSequence.Element == Element {
-        var source: Observable<Element>?
-        var subscription: Disposable?
+        nonisolated(unsafe) var source: Observable<Element>?
+        nonisolated(unsafe) var subscription: Disposable?
         let observer = self.createObserver(Element.self)
         
         _ = self.scheduleAbsoluteVirtual((), time: created) { _ in
@@ -130,7 +130,7 @@ public class TestScheduler : VirtualTimeScheduler<TestSchedulerVirtualTimeConver
      - parameter create: Factory method to create an observable convertible sequence.
      - returns: Observer with timestamped recordings of events that were received during the virtual time window when the subscription to the source sequence was active.
      */
-    public func start<Element, OutputSequence: ObservableConvertibleType>(disposed: TestTime, create: @escaping () -> OutputSequence)
+    public func start<Element, OutputSequence: ObservableConvertibleType>(disposed: TestTime, create: @escaping @Sendable () -> OutputSequence)
         -> TestableObserver<Element> where OutputSequence.Element == Element {
         self.start(created: Defaults.created, subscribed: Defaults.subscribed, disposed: disposed, create: create)
     }
@@ -146,7 +146,7 @@ public class TestScheduler : VirtualTimeScheduler<TestSchedulerVirtualTimeConver
      - parameter create: Factory method to create an observable convertible sequence.
      - returns: Observer with timestamped recordings of events that were received during the virtual time window when the subscription to the source sequence was active.
      */
-    public func start<Element, OutputSequence: ObservableConvertibleType>(_ create: @escaping () -> OutputSequence)
+    public func start<Element, OutputSequence: ObservableConvertibleType>(_ create: @escaping @Sendable () -> OutputSequence)
         -> TestableObserver<Element> where OutputSequence.Element == Element {
          self.start(created: Defaults.created, subscribed: Defaults.subscribed, disposed: Defaults.disposed, create: create)
     }
diff --git a/Tests/RxCocoaTests/DelegateProxyTest.swift b/Tests/RxCocoaTests/DelegateProxyTest.swift
index b0f930f03..23d632ffd 100644
--- a/Tests/RxCocoaTests/DelegateProxyTest.swift
+++ b/Tests/RxCocoaTests/DelegateProxyTest.swift
@@ -97,12 +97,12 @@ final class DelegateProxyTest : RxTest {
         
         view.delegate = mock
         
-        var observedFeedRequestSentMessage = false
-        var observedMessageInvoked = false
-        var events: [MessageProcessingStage] = []
+        nonisolated(unsafe) var observedFeedRequestSentMessage = false
+        nonisolated(unsafe) var observedMessageInvoked = false
+        nonisolated(unsafe) var events: [MessageProcessingStage] = []
 
-        var delegates: [NSObject?] = []
-        var responds: [Bool] = []
+        nonisolated(unsafe) var delegates: [NSObject?] = []
+        nonisolated(unsafe) var responds: [Bool] = []
 
         _ = view.rx.observeWeakly(NSObject.self, "delegate").skip(1).subscribe(onNext: { delegate in
             delegates.append(delegate)
@@ -155,8 +155,8 @@ final class DelegateProxyTest : RxTest {
         
         view.delegate = mock
         
-        var nMessages = 0
-        var invoked = false
+        nonisolated(unsafe) var nMessages = 0
+        nonisolated(unsafe) var invoked = false
         
         let d = view.rx.proxy.sentMessage(#selector(ThreeDSectionedViewProtocol.threeDView(_:didLearnSomething:)))
             .subscribe(onNext: { n in
@@ -209,13 +209,13 @@ final class DelegateProxyTest : RxTest {
         
         let sentArgument = IndexPath(index: 0)
         
-        var receivedArgumentSentMessage: IndexPath? = nil
-        var receivedArgumentMethodInvoked: IndexPath? = nil
+        nonisolated(unsafe) var receivedArgumentSentMessage: IndexPath? = nil
+        nonisolated(unsafe) var receivedArgumentMethodInvoked: IndexPath? = nil
 
-        var events: [MessageProcessingStage] = []
+        nonisolated(unsafe) var events: [MessageProcessingStage] = []
 
-        var delegates: [NSObject?] = []
-        var responds: [Bool] = []
+        nonisolated(unsafe) var delegates: [NSObject?] = []
+        nonisolated(unsafe) var responds: [Bool] = []
 
         _ = view.rx.observeWeakly(NSObject.self, "delegate").skip(1).subscribe(onNext: { delegate in
             delegates.append(delegate)
@@ -278,8 +278,8 @@ final class DelegateProxyTest : RxTest {
         
         view.delegate = mock
         
-        var completedSentMessage = false
-        var completedMethodInvoked = false
+        nonisolated(unsafe) var completedSentMessage = false
+        nonisolated(unsafe) var completedMethodInvoked = false
 
         autoreleasepool {
             XCTAssertTrue(!mock.responds(to: NSSelectorFromString("threeDView:threeDView:didGetXXX:")))
@@ -359,7 +359,7 @@ extension DelegateProxyTest {
         XCTAssertTrue(view.delegate === proxy)
         XCTAssertTrue(view.rx.proxy.forwardToDelegate() === mock)
 
-        var latestValue: Int? = nil
+        nonisolated(unsafe) var latestValue: Int? = nil
         _ = view.rx.testIt.subscribe(onNext: {
             latestValue = $0
         })
@@ -383,7 +383,7 @@ extension DelegateProxyTest {
 // MARK: Testing extensions
 
 extension DelegateProxyTest {
-    func performDelegateTest<Control: TestDelegateControl, ExtendedProxy: DelegateProxyType>( _ createControl: @autoclosure() -> Control, make: @escaping (Control) -> ExtendedProxy) {
+    func performDelegateTest<Control: TestDelegateControl, ExtendedProxy: DelegateProxyType>( _ createControl: @autoclosure() -> Control, make: @escaping @Sendable (Control) -> ExtendedProxy) {
         ExtendedProxy.register(make: make)
         var control: Control!
 
@@ -391,12 +391,12 @@ extension DelegateProxyTest {
             control = createControl()
         }
 
-        var receivedValueSentMessage: Int!
-        var receivedValueMethodInvoked: Int!
-        var completedSentMessage = false
-        var completedMethodInvoked = false
-        var deallocated = false
-        var stages: [MessageProcessingStage] = []
+        nonisolated(unsafe) var receivedValueSentMessage: Int!
+        nonisolated(unsafe) var receivedValueMethodInvoked: Int!
+        nonisolated(unsafe) var completedSentMessage = false
+        nonisolated(unsafe) var completedMethodInvoked = false
+        nonisolated(unsafe) var deallocated = false
+        nonisolated(unsafe) var stages: [MessageProcessingStage] = []
         let expectation = self.expectation(description: "dealloc")
         autoreleasepool {
             _ = control.testSentMessage.subscribe(onNext: { value in
diff --git a/Tests/RxCocoaTests/KVOObservableTests.swift b/Tests/RxCocoaTests/KVOObservableTests.swift
index 3a19248eb..35e4c433f 100644
--- a/Tests/RxCocoaTests/KVOObservableTests.swift
+++ b/Tests/RxCocoaTests/KVOObservableTests.swift
@@ -34,7 +34,7 @@ final class Parent : NSObject {
 
     @objc dynamic var val: String = ""
 
-    init(callback: @escaping (String?) -> Void) {
+    init(callback: @escaping @Sendable (String?) -> Void) {
         super.init()
         
         self.rx.observe(String.self, "val", options: [.initial, .new], retainSelf: false)
@@ -50,7 +50,7 @@ final class Parent : NSObject {
 final class Child : NSObject {
     let disposeBag = DisposeBag()
     
-    init(parent: ParentWithChild, callback: @escaping (String?) -> Void) {
+    init(parent: ParentWithChild, callback: @escaping @Sendable (String?) -> Void) {
         super.init()
         parent.rx.observe(String.self, "val", options: [.initial, .new], retainSelf: false)
             .subscribe(onNext: callback)
@@ -67,7 +67,7 @@ final class ParentWithChild : NSObject {
     
     var child: Child? = nil
     
-    init(callback: @escaping (String?) -> Void) {
+    init(callback: @escaping @Sendable (String?) -> Void) {
         super.init()
         child = Child(parent: self, callback: callback)
     }
@@ -143,8 +143,8 @@ extension KVOObservableTests {
     func testKeyPathObservation_DefaultOptions() {
         testClass = TestClass()
         let os = testClass.rx.observe(\.pr)
-        var latest: String?
-        var completed = false
+        nonisolated(unsafe) var latest: String?
+        nonisolated(unsafe) var completed = false
 
         _ = os.subscribe(onNext: { latest = $0 },
                          onCompleted: { completed = true })
@@ -171,7 +171,7 @@ extension KVOObservableTests {
     func testKeyPathObservation_NewAndInitialOptions() {
         let testClass = TestClass()
         let os = testClass.rx.observe(\.pr, options: [.new, .initial])
-        var latest: String?
+        nonisolated(unsafe) var latest: String?
 
         let d = os.subscribe(onNext: { latest = $0 })
         testClass.pr = "1"
@@ -195,8 +195,8 @@ extension KVOObservableTests {
     func testKeyPathObservation_NewOptions() {
         testClass = TestClass()
         let os = testClass.rx.observe(\.pr, options: [.new])
-        var latest: String?
-        var completed = false
+        nonisolated(unsafe) var latest: String?
+        nonisolated(unsafe) var completed = false
 
         _ = os.subscribe(onNext: { latest = $0 },
                          onCompleted: { completed = true })
@@ -230,7 +230,7 @@ extension KVOObservableTests {
         
         let os = testClass.rx.observe(String.self, "pr", options: .new)
         
-        var latest: String?
+        nonisolated(unsafe) var latest: String?
         
         let d = os.subscribe(onNext: { latest = $0 })
         
@@ -264,7 +264,7 @@ extension KVOObservableTests {
         
         let os = testClass.rx.observe(String.self, "pr", options: [.initial, .new])
         
-        var latest: String?
+        nonisolated(unsafe) var latest: String?
         
         let d = os.subscribe(onNext: { latest = $0 })
         
@@ -298,7 +298,7 @@ extension KVOObservableTests {
         
         let os = testClass.rx.observe(String.self, "pr")
         
-        var latest: String?
+        nonisolated(unsafe) var latest: String?
         
         let d = os.subscribe(onNext: { latest = $0 })
         
@@ -328,8 +328,8 @@ extension KVOObservableTests {
     }
     
     func test_ObserveAndDontRetainWorks() {
-        var latest: String?
-        var isDisposed = false
+        nonisolated(unsafe) var latest: String?
+        nonisolated(unsafe) var isDisposed = false
 
         parent = Parent { n in
             latest = n
@@ -355,8 +355,8 @@ extension KVOObservableTests {
     }
     
     func test_ObserveAndDontRetainWorks2() {
-        var latest: String?
-        var isDisposed = false
+        nonisolated(unsafe) var latest: String?
+        nonisolated(unsafe) var isDisposed = false
         
         parentWithChild = ParentWithChild { n in
             latest = n
@@ -388,8 +388,8 @@ extension KVOObservableTests {
 extension KVOObservableTests {
     
     func testObserveWeak_SimpleStrongProperty() {
-        var latest: String?
-        var isDisposed = false
+        nonisolated(unsafe) var latest: String?
+        nonisolated(unsafe) var isDisposed = false
         
         hasStrongProperty = HasStrongProperty()
         
@@ -418,8 +418,8 @@ extension KVOObservableTests {
     }
     
     func testObserveWeak_SimpleWeakProperty() {
-        var latest: String?
-        var isDisposed = false
+        nonisolated(unsafe) var latest: String?
+        nonisolated(unsafe) var isDisposed = false
         
         hasWeakProperty = HasWeakProperty()
         
@@ -450,8 +450,8 @@ extension KVOObservableTests {
     }
 
     func testObserveWeak_ObserveFirst_Weak_Strong_Basic() {
-        var latest: String?
-        var isDisposed = false
+        nonisolated(unsafe) var latest: String?
+        nonisolated(unsafe) var isDisposed = false
         
         hasStrongProperty = HasStrongProperty()
         hasWeakProperty = HasWeakProperty()
@@ -489,8 +489,8 @@ extension KVOObservableTests {
     }
     
     func testObserveWeak_Weak_Strong_Observe_Basic() {
-        var latest: String?
-        var isDisposed = false
+        nonisolated(unsafe) var latest: String?
+        nonisolated(unsafe) var isDisposed = false
         
         hasStrongProperty = HasStrongProperty()
         hasWeakProperty = HasWeakProperty()
@@ -525,8 +525,8 @@ extension KVOObservableTests {
     }
     
     func testObserveWeak_ObserveFirst_Strong_Weak_Basic() {
-        var latest: String?
-        var isDisposed = false
+        nonisolated(unsafe) var latest: String?
+        nonisolated(unsafe) var isDisposed = false
         
         hasWeakProperty = HasWeakProperty()
         hasStrongProperty = HasStrongProperty()
@@ -564,8 +564,8 @@ extension KVOObservableTests {
     }
     
     func testObserveWeak_Strong_Weak_Observe_Basic() {
-        var latest: String?
-        var isDisposed = false
+        nonisolated(unsafe) var latest: String?
+        nonisolated(unsafe) var isDisposed = false
         
         hasWeakProperty = HasWeakProperty()
         hasStrongProperty = HasStrongProperty()
@@ -601,16 +601,16 @@ extension KVOObservableTests {
     
     // compiler won't release weak references otherwise :(
     func _testObserveWeak_Strong_Weak_Observe_NilLastPropertyBecauseOfWeak() -> (HasWeakProperty, NSObject?, Observable<Void>) {
-        var dealloc: Observable<Void>! = nil
+        nonisolated(unsafe) var dealloc: Observable<Void>! = nil
         let child: HasWeakProperty! = HasWeakProperty()
-        var latest: NSObject? = nil
+        nonisolated(unsafe) var latest: NSObject? = nil
         
         autoreleasepool {
             let root: HasStrongProperty! = HasStrongProperty()
             
             root.property = child
             
-            var one: NSObject! = nil
+            nonisolated(unsafe) var one: NSObject! = nil
             
             one = NSObject()
             
@@ -634,7 +634,7 @@ extension KVOObservableTests {
     }
     
     func testObserveWeak_Strong_Weak_Observe_NilLastPropertyBecauseOfWeak() {
-        var gone = false
+        nonisolated(unsafe) var gone = false
         let (child, latest, dealloc) = _testObserveWeak_Strong_Weak_Observe_NilLastPropertyBecauseOfWeak()
         _ = dealloc
             .subscribe(onNext: { n in
@@ -647,9 +647,9 @@ extension KVOObservableTests {
     }
     
     func _testObserveWeak_Weak_Weak_Weak_middle_NilifyCorrectly() -> (HasWeakProperty, NSObject?, Observable<Void>) {
-        var dealloc: Observable<Void>! = nil
-        var middle: HasWeakProperty! = HasWeakProperty()
-        var latest: NSObject? = nil
+        nonisolated(unsafe) var dealloc: Observable<Void>! = nil
+        nonisolated(unsafe) var middle: HasWeakProperty! = HasWeakProperty()
+        nonisolated(unsafe) var latest: NSObject? = nil
         let root: HasWeakProperty! = HasWeakProperty()
         
         autoreleasepool {
@@ -683,7 +683,7 @@ extension KVOObservableTests {
     func testObserveWeak_Weak_Weak_Weak_middle_NilifyCorrectly() {
         let (root, latest, deallocatedMiddle) = _testObserveWeak_Weak_Weak_Weak_middle_NilifyCorrectly()
         
-        var gone = false
+        nonisolated(unsafe) var gone = false
         
         _ = deallocatedMiddle
             .subscribe(onCompleted: {
@@ -696,9 +696,9 @@ extension KVOObservableTests {
     }
     
     func testObserveWeak_TargetDeallocated() {
-        var root: HasStrongProperty! = HasStrongProperty()
+        nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
         
-        var latest: String? = nil
+        nonisolated(unsafe) var latest: String? = nil
         
         root.property = "a".duplicate()
         
@@ -712,7 +712,7 @@ extension KVOObservableTests {
        
         XCTAssertTrue(latest == "a")
      
-        var rootDeallocated = false
+        nonisolated(unsafe) var rootDeallocated = false
         
         _ = root
             .rx.deallocated
@@ -727,9 +727,9 @@ extension KVOObservableTests {
     }
     
     func testObserveWeakWithOptions_ObserveNotInitialValue() {
-        var root: HasStrongProperty! = HasStrongProperty()
+        nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
         
-        var latest: String? = nil
+        nonisolated(unsafe) var latest: String? = nil
         
         root.property = "a".duplicate()
         
@@ -747,7 +747,7 @@ extension KVOObservableTests {
 
         XCTAssertTrue(latest == "b")
         
-        var rootDeallocated = false
+        nonisolated(unsafe) var rootDeallocated = false
         
         _ = root
             .rx.deallocated
@@ -764,9 +764,9 @@ extension KVOObservableTests {
     #if os(macOS)
     // just making sure it's all the same for NS extensions
     func testObserve_ObserveNSRect() {
-        var root: HasStrongProperty! = HasStrongProperty()
+        nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
         
-        var latest: NSRect? = nil
+        nonisolated(unsafe) var latest: NSRect? = nil
         
         XCTAssertTrue(latest == nil)
         
@@ -780,7 +780,7 @@ extension KVOObservableTests {
         
         XCTAssertTrue(latest == NSRect(x: -2, y: 0, width: 0, height: 1))
         
-        var rootDeallocated = false
+        nonisolated(unsafe) var rootDeallocated = false
         
         _ = root
             .rx.deallocated
@@ -800,9 +800,9 @@ extension KVOObservableTests {
     
     // let's just check for one, other ones should have the same check
     func testObserve_ObserveCGRectForBiggerStructureDoesntCrashPropertyTypeReturnsNil() {
-        var root: HasStrongProperty! = HasStrongProperty()
+        nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
         
-        var latest: CGSize? = nil
+        nonisolated(unsafe) var latest: CGSize? = nil
         
         XCTAssertTrue(latest == nil)
         
@@ -821,7 +821,7 @@ extension KVOObservableTests {
         
         XCTAssertTrue(latest == nil)
         
-        var rootDeallocated = false
+        nonisolated(unsafe) var rootDeallocated = false
         
         _ = root
             .rx.deallocated
@@ -836,9 +836,9 @@ extension KVOObservableTests {
     }
     
     func testObserve_ObserveCGRect() {
-        var root: HasStrongProperty! = HasStrongProperty()
+        nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
         
-        var latest: CGRect? = nil
+        nonisolated(unsafe) var latest: CGRect? = nil
         
         XCTAssertTrue(latest == nil)
         
@@ -857,7 +857,7 @@ extension KVOObservableTests {
         
         XCTAssertTrue(latest == CGRect(x: -2, y: 0, width: 0, height: 1))
         
-        var rootDeallocated = false
+        nonisolated(unsafe) var rootDeallocated = false
         
         _ = root
             .rx.deallocated
@@ -872,9 +872,9 @@ extension KVOObservableTests {
     }
     
     func testObserve_ObserveCGSize() {
-        var root: HasStrongProperty! = HasStrongProperty()
+        nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
         
-        var latest: CGSize? = nil
+        nonisolated(unsafe) var latest: CGSize? = nil
         
         XCTAssertTrue(latest == nil)
         
@@ -893,7 +893,7 @@ extension KVOObservableTests {
         
         XCTAssertTrue(latest == CGSize(width: 56, height: 1))
         
-        var rootDeallocated = false
+        nonisolated(unsafe) var rootDeallocated = false
         
         _ = root
             .rx.deallocated
@@ -908,9 +908,9 @@ extension KVOObservableTests {
     }
     
     func testObserve_ObserveCGPoint() {
-        var root: HasStrongProperty! = HasStrongProperty()
+        nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
         
-        var latest: CGPoint? = nil
+        nonisolated(unsafe) var latest: CGPoint? = nil
         
         XCTAssertTrue(latest == nil)
         
@@ -928,7 +928,7 @@ extension KVOObservableTests {
         
         XCTAssertTrue(latest == CGPoint(x: -100, y: 1))
         
-        var rootDeallocated = false
+        nonisolated(unsafe) var rootDeallocated = false
         
         _ = root
             .rx.deallocated
@@ -944,9 +944,9 @@ extension KVOObservableTests {
     
     
     func testObserveWeak_ObserveCGRect() {
-        var root: HasStrongProperty! = HasStrongProperty()
+        nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
         
-        var latest: CGRect? = nil
+        nonisolated(unsafe) var latest: CGRect? = nil
         
         XCTAssertTrue(latest == nil)
         
@@ -961,7 +961,7 @@ extension KVOObservableTests {
         
         XCTAssertTrue(latest == CGRect(x: -2, y: 0, width: 0, height: 1))
         
-        var rootDeallocated = false
+        nonisolated(unsafe) var rootDeallocated = false
         
         _ = root
             .rx.deallocated
@@ -976,9 +976,9 @@ extension KVOObservableTests {
     }
     
     func testObserveWeak_ObserveCGSize() {
-        var root: HasStrongProperty! = HasStrongProperty()
+        nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
         
-        var latest: CGSize? = nil
+        nonisolated(unsafe) var latest: CGSize? = nil
         
         XCTAssertTrue(latest == nil)
         
@@ -993,7 +993,7 @@ extension KVOObservableTests {
         
         XCTAssertTrue(latest == CGSize(width: 56, height: 1))
         
-        var rootDeallocated = false
+        nonisolated(unsafe) var rootDeallocated = false
         
         _ = root
             .rx.deallocated
@@ -1008,9 +1008,9 @@ extension KVOObservableTests {
     }
     
     func testObserveWeak_ObserveCGPoint() {
-        var root: HasStrongProperty! = HasStrongProperty()
+        nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
         
-        var latest: CGPoint? = nil
+        nonisolated(unsafe) var latest: CGPoint? = nil
         
         XCTAssertTrue(latest == nil)
         
@@ -1026,7 +1026,7 @@ extension KVOObservableTests {
         
         XCTAssertTrue(latest == CGPoint(x: -100, y: 1))
         
-        var rootDeallocated = false
+        nonisolated(unsafe) var rootDeallocated = false
         
         _ = root
             .rx.deallocated
@@ -1041,9 +1041,9 @@ extension KVOObservableTests {
     }
     
     func testObserveWeak_ObserveInt() {
-        var root: HasStrongProperty! = HasStrongProperty()
+        nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
         
-        var latest: Int? = nil
+        nonisolated(unsafe) var latest: Int? = nil
         
         XCTAssertTrue(latest == nil)
         
@@ -1058,7 +1058,7 @@ extension KVOObservableTests {
         
         XCTAssertTrue(latest == 10)
         
-        var rootDeallocated = false
+        nonisolated(unsafe) var rootDeallocated = false
         
         _ = root
             .rx.deallocated
@@ -1073,9 +1073,9 @@ extension KVOObservableTests {
     }
 
     func testObserveWeak_PropertyDoesntExist() {
-        var root: HasStrongProperty! = HasStrongProperty()
+        nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
         
-        var lastError: Swift.Error? = nil
+        nonisolated(unsafe) var lastError: Swift.Error? = nil
         
         _ = root.rx.observeWeakly(NSNumber.self, "notExist")
             .subscribe(onError: { error in
@@ -1085,7 +1085,7 @@ extension KVOObservableTests {
         XCTAssertTrue(lastError != nil)
         lastError = nil
 
-        var rootDeallocated = false
+        nonisolated(unsafe) var rootDeallocated = false
         
         _ = root
             .rx.deallocated
@@ -1099,9 +1099,9 @@ extension KVOObservableTests {
     }
     
     func testObserveWeak_HierarchyPropertyDoesntExist() {
-        var root: HasStrongProperty! = HasStrongProperty()
+        nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
         
-        var lastError: Swift.Error? = nil
+        nonisolated(unsafe) var lastError: Swift.Error? = nil
         
         _ = root.rx.observeWeakly(NSNumber.self, "property.notExist")
             .subscribe(onError: { error in
@@ -1114,7 +1114,7 @@ extension KVOObservableTests {
 
         XCTAssertTrue(lastError != nil)
         
-        var rootDeallocated = false
+        nonisolated(unsafe) var rootDeallocated = false
         
         _ = root
             .rx.deallocated
@@ -1133,9 +1133,9 @@ extension KVOObservableTests {
 
 extension KVOObservableTests {
     func testObserve_ObserveIntegerRepresentable() {
-        var root: HasStrongProperty! = HasStrongProperty()
+        nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
 
-        var latest: Int?
+        nonisolated(unsafe) var latest: Int?
 
         XCTAssertTrue(latest == nil)
 
@@ -1149,7 +1149,7 @@ extension KVOObservableTests {
 
         XCTAssertTrue(latest == 2)
 
-        var rootDeallocated = false
+        nonisolated(unsafe) var rootDeallocated = false
 
         _ = root
             .rx.deallocated
@@ -1166,9 +1166,9 @@ extension KVOObservableTests {
     }
 
     func testObserve_ObserveUIntegerRepresentable() {
-        var root: HasStrongProperty! = HasStrongProperty()
+        nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
 
-        var latest: UInt?
+        nonisolated(unsafe) var latest: UInt?
 
         XCTAssertTrue(latest == nil)
 
@@ -1182,7 +1182,7 @@ extension KVOObservableTests {
 
         XCTAssertTrue(latest == 2)
 
-        var rootDeallocated = false
+        nonisolated(unsafe) var rootDeallocated = false
 
         _ = root
             .rx.deallocated
@@ -1202,9 +1202,9 @@ extension KVOObservableTests {
 #if !DISABLE_SWIZZLING
     extension KVOObservableTests {
         func testObserveWeak_ObserveIntegerRepresentable() {
-            var root: HasStrongProperty! = HasStrongProperty()
+            nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
 
-            var latest: Int?
+            nonisolated(unsafe) var latest: Int?
 
             XCTAssertTrue(latest == nil)
 
@@ -1220,7 +1220,7 @@ extension KVOObservableTests {
 
             XCTAssertTrue(latest == 2)
 
-            var rootDeallocated = false
+            nonisolated(unsafe) var rootDeallocated = false
 
             _ = root
                 .rx.deallocated
@@ -1235,9 +1235,9 @@ extension KVOObservableTests {
         }
 
         func testObserveWeak_ObserveUIntegerRepresentable() {
-            var root: HasStrongProperty! = HasStrongProperty()
+            nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
 
-            var latest: UInt?
+            nonisolated(unsafe) var latest: UInt?
 
             XCTAssertTrue(latest == nil)
 
@@ -1253,7 +1253,7 @@ extension KVOObservableTests {
 
             XCTAssertTrue(latest == 2)
 
-            var rootDeallocated = false
+            nonisolated(unsafe) var rootDeallocated = false
 
             _ = root
                 .rx.deallocated
@@ -1272,9 +1272,9 @@ extension KVOObservableTests {
 // MARK: RawRepresentable
 extension KVOObservableTests {
     func testObserve_ObserveIntEnum() {
-        var root: HasStrongProperty! = HasStrongProperty()
+        nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
 
-        var latest: IntEnum?
+        nonisolated(unsafe) var latest: IntEnum?
 
         XCTAssertTrue(latest == nil)
 
@@ -1288,7 +1288,7 @@ extension KVOObservableTests {
 
         XCTAssertTrue(latest == .two)
 
-        var rootDeallocated = false
+        nonisolated(unsafe) var rootDeallocated = false
 
         _ = root
             .rx.deallocated
@@ -1305,9 +1305,9 @@ extension KVOObservableTests {
     }
 
     func testObserve_ObserveInt32Enum() {
-        var root: HasStrongProperty! = HasStrongProperty()
+        nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
 
-        var latest: Int32Enum?
+        nonisolated(unsafe) var latest: Int32Enum?
 
         XCTAssertTrue(latest == nil)
 
@@ -1321,7 +1321,7 @@ extension KVOObservableTests {
 
         XCTAssertTrue(latest == .two)
 
-        var rootDeallocated = false
+        nonisolated(unsafe) var rootDeallocated = false
 
         _ = root
             .rx.deallocated
@@ -1338,9 +1338,9 @@ extension KVOObservableTests {
     }
 
     func testObserve_ObserveInt64Enum() {
-        var root: HasStrongProperty! = HasStrongProperty()
+        nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
 
-        var latest: Int64Enum?
+        nonisolated(unsafe) var latest: Int64Enum?
 
         XCTAssertTrue(latest == nil)
 
@@ -1354,7 +1354,7 @@ extension KVOObservableTests {
 
         XCTAssertTrue(latest == .two)
 
-        var rootDeallocated = false
+        nonisolated(unsafe) var rootDeallocated = false
 
         _ = root
             .rx.deallocated
@@ -1372,9 +1372,9 @@ extension KVOObservableTests {
 
 
     func testObserve_ObserveUIntEnum() {
-        var root: HasStrongProperty! = HasStrongProperty()
+        nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
 
-        var latest: UIntEnum?
+        nonisolated(unsafe) var latest: UIntEnum?
 
         XCTAssertTrue(latest == nil)
 
@@ -1388,7 +1388,7 @@ extension KVOObservableTests {
 
         XCTAssertTrue(latest == .two)
 
-        var rootDeallocated = false
+        nonisolated(unsafe) var rootDeallocated = false
 
         _ = root
             .rx.deallocated
@@ -1405,9 +1405,9 @@ extension KVOObservableTests {
     }
 
     func testObserve_ObserveUInt32Enum() {
-        var root: HasStrongProperty! = HasStrongProperty()
+        nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
 
-        var latest: UInt32Enum?
+        nonisolated(unsafe) var latest: UInt32Enum?
 
         XCTAssertTrue(latest == nil)
 
@@ -1421,7 +1421,7 @@ extension KVOObservableTests {
 
         XCTAssertTrue(latest == .two)
 
-        var rootDeallocated = false
+        nonisolated(unsafe) var rootDeallocated = false
 
         _ = root
             .rx.deallocated
@@ -1438,9 +1438,9 @@ extension KVOObservableTests {
     }
 
     func testObserve_ObserveUInt64Enum() {
-        var root: HasStrongProperty! = HasStrongProperty()
+        nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
 
-        var latest: UInt64Enum?
+        nonisolated(unsafe) var latest: UInt64Enum?
 
         XCTAssertTrue(latest == nil)
 
@@ -1454,7 +1454,7 @@ extension KVOObservableTests {
 
         XCTAssertTrue(latest == .two)
 
-        var rootDeallocated = false
+        nonisolated(unsafe) var rootDeallocated = false
 
         _ = root
             .rx.deallocated
@@ -1474,9 +1474,9 @@ extension KVOObservableTests {
 #if !DISABLE_SWIZZLING
 extension KVOObservableTests {
     func testObserveWeak_ObserveIntEnum() {
-        var root: HasStrongProperty! = HasStrongProperty()
+        nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
 
-        var latest: IntEnum?
+        nonisolated(unsafe) var latest: IntEnum?
 
         XCTAssertTrue(latest == nil)
 
@@ -1491,7 +1491,7 @@ extension KVOObservableTests {
 
         XCTAssertTrue(latest == .two)
 
-        var rootDeallocated = false
+        nonisolated(unsafe) var rootDeallocated = false
 
         _ = root
             .rx.deallocated
@@ -1506,9 +1506,9 @@ extension KVOObservableTests {
     }
 
     func testObserveWeak_ObserveInt32Enum() {
-        var root: HasStrongProperty! = HasStrongProperty()
+        nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
 
-        var latest: Int32Enum?
+        nonisolated(unsafe) var latest: Int32Enum?
 
         XCTAssertTrue(latest == nil)
 
@@ -1523,7 +1523,7 @@ extension KVOObservableTests {
 
         XCTAssertTrue(latest == .two)
 
-        var rootDeallocated = false
+        nonisolated(unsafe) var rootDeallocated = false
 
         _ = root
             .rx.deallocated
@@ -1538,9 +1538,9 @@ extension KVOObservableTests {
     }
 
     func testObserveWeak_ObserveInt64Enum() {
-        var root: HasStrongProperty! = HasStrongProperty()
+        nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
 
-        var latest: Int64Enum?
+        nonisolated(unsafe) var latest: Int64Enum?
 
         XCTAssertTrue(latest == nil)
 
@@ -1555,7 +1555,7 @@ extension KVOObservableTests {
 
         XCTAssertTrue(latest == .two)
 
-        var rootDeallocated = false
+        nonisolated(unsafe) var rootDeallocated = false
 
         _ = root
             .rx.deallocated
@@ -1570,9 +1570,9 @@ extension KVOObservableTests {
     }
 
     func testObserveWeak_ObserveUIntEnum() {
-        var root: HasStrongProperty! = HasStrongProperty()
+        nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
 
-        var latest: UIntEnum?
+        nonisolated(unsafe) var latest: UIntEnum?
 
         XCTAssertTrue(latest == nil)
 
@@ -1587,7 +1587,7 @@ extension KVOObservableTests {
 
         XCTAssertTrue(latest == .two)
 
-        var rootDeallocated = false
+        nonisolated(unsafe) var rootDeallocated = false
 
         _ = root
             .rx.deallocated
@@ -1602,9 +1602,9 @@ extension KVOObservableTests {
     }
 
     func testObserveWeak_ObserveUInt32Enum() {
-        var root: HasStrongProperty! = HasStrongProperty()
+        nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
 
-        var latest: UInt32Enum?
+        nonisolated(unsafe) var latest: UInt32Enum?
 
         XCTAssertTrue(latest == nil)
 
@@ -1619,7 +1619,7 @@ extension KVOObservableTests {
 
         XCTAssertTrue(latest == .two)
 
-        var rootDeallocated = false
+        nonisolated(unsafe) var rootDeallocated = false
 
         _ = root
             .rx.deallocated
@@ -1634,9 +1634,9 @@ extension KVOObservableTests {
     }
 
     func testObserveWeak_ObserveUInt64Enum() {
-        var root: HasStrongProperty! = HasStrongProperty()
+        nonisolated(unsafe) var root: HasStrongProperty! = HasStrongProperty()
 
-        var latest: UInt32Enum?
+        nonisolated(unsafe) var latest: UInt32Enum?
 
         XCTAssertTrue(latest == nil)
 
@@ -1651,7 +1651,7 @@ extension KVOObservableTests {
 
         XCTAssertTrue(latest == .two)
 
-        var rootDeallocated = false
+        nonisolated(unsafe) var rootDeallocated = false
 
         _ = root
             .rx.deallocated
diff --git a/Tests/RxCocoaTests/RxTest+Controls.swift b/Tests/RxCocoaTests/RxTest+Controls.swift
index be88ece66..5bb44e440 100644
--- a/Tests/RxCocoaTests/RxTest+Controls.swift
+++ b/Tests/RxCocoaTests/RxTest+Controls.swift
@@ -35,10 +35,10 @@ extension RxTest {
 
         let completeExpectation = XCTestExpectation(description: "completion")
         let deallocateExpectation = XCTestExpectation(description: "deallocation")
-        var lastReturnedPropertyValue: T?
+        nonisolated(unsafe) var lastReturnedPropertyValue: T?
 
         autoreleasepool {
-            var control: C! = createControl()
+            nonisolated(unsafe) var control: C! = createControl()
 
             let property = propertySelector(control)
 
@@ -69,13 +69,13 @@ extension RxTest {
         )
     }
 
-    func ensureEventDeallocated<C, T>(_ createControl: @escaping () -> C, file: StaticString = #file, line: UInt = #line, _ eventSelector: (C) -> ControlEvent<T>) where C: NSObject {
+    func ensureEventDeallocated<C, T>(_ createControl: @escaping @Sendable () -> C, file: StaticString = #file, line: UInt = #line, _ eventSelector: (C) -> ControlEvent<T>) where C: NSObject {
         ensureEventDeallocated({ () -> (C, Disposable) in (createControl(), Disposables.create()) }, file: file, line: line, eventSelector)
     }
 
     func ensureEventDeallocated<C, T>(_ createControl: () -> (C, Disposable), file: StaticString = #file, line: UInt = #line, _ eventSelector: (C) -> ControlEvent<T>) where C: NSObject {
-        var completed = false
-        var deallocated = false
+        nonisolated(unsafe) var completed = false
+        nonisolated(unsafe) var deallocated = false
         let outerDisposable = SingleAssignmentDisposable()
 
         autoreleasepool {
@@ -101,7 +101,7 @@ extension RxTest {
     }
 
     func ensureControlObserverHasWeakReference<C, T>(file: StaticString = #file, line: UInt = #line, _ createControl: @autoclosure() -> (C), _ observerSelector: (C) -> AnyObserver<T>, _ observableSelector: () -> (Observable<T>)) where C: NSObject {
-        var deallocated = false
+        nonisolated(unsafe) var deallocated = false
 
         let disposeBag = DisposeBag()
 
diff --git a/Tests/RxCocoaTests/SentMessageTest.swift b/Tests/RxCocoaTests/SentMessageTest.swift
index 430f4e23d..8a12ae0b2 100644
--- a/Tests/RxCocoaTests/SentMessageTest.swift
+++ b/Tests/RxCocoaTests/SentMessageTest.swift
@@ -461,7 +461,7 @@ extension SentMessageTest {
     <
         BaseClass: SentMessageTestClassCreationProtocol & NSObjectProtocol,
         TargetClass: SentMessageTestClassCreationProtocol & NSObjectProtocol
-    >(_ baseClass: BaseClass.Type, _ targetClass: TargetClass.Type, _ method: Selector, _ invoke: @escaping (BaseClass) -> [[MethodParameters]]) {
+    >(_ baseClass: BaseClass.Type, _ targetClass: TargetClass.Type, _ method: Selector, _ invoke: @escaping @Sendable (BaseClass) -> [[MethodParameters]]) {
         // now force forwarding mechanism for normal class
         ensureGlobalRuntimeChangesAreCached(
             createNormalInstance(),
@@ -559,8 +559,8 @@ extension SentMessageTest {
 extension SentMessageTest {
     func testBasicForwardingCase() {
         let target = SentMessageTest_forwarding_basic()
-        var messages = [[Any]]()
-        var messageStage: [MessageProcessingStage] = []
+        nonisolated(unsafe) var messages = [[Any]]()
+        nonisolated(unsafe) var messageStage: [MessageProcessingStage] = []
 
         let d = target.rx.sentMessage(#selector(SentMessageTestBase_shared.message_allSupportedParameters(_:p2:p3:p4:p5:p6:p7:p8:p9:p10:p11:p12:p13:p14:p15:p16:))).subscribe(onNext: { n in
                 messages.append(n)
@@ -795,13 +795,13 @@ extension SentMessageTest {
         let target = SentMessageTest_shared()
 
         let messages = target.rx.sentMessage(#selector(SentMessageTestBase_shared.justCalledBool(toSay:)))
-        var stages: [MessageProcessingStage] = []
+        nonisolated(unsafe) var stages: [MessageProcessingStage] = []
 
         let kvo = target.rx.observe(NSArray.self, "messages")
             .subscribe(onNext: { _ in
             })
 
-        var recordedMessages = [MethodParameters]()
+        nonisolated(unsafe) var recordedMessages = [MethodParameters]()
         let methodObserving = messages.subscribe(onNext: { n in
             stages.append(.sentMessage)
             recordedMessages.append(n)
@@ -827,13 +827,13 @@ extension SentMessageTest {
         let target = SentMessageTest_shared()
 
         let messages = target.rx.methodInvoked(#selector(SentMessageTestBase_shared.justCalledBool(toSay:)))
-        var stages: [MessageProcessingStage] = []
+        nonisolated(unsafe) var stages: [MessageProcessingStage] = []
 
         let kvo = target.rx.observe(NSArray.self, "messages")
             .subscribe(onNext: { _ in
             })
 
-        var recordedMessages = [MethodParameters]()
+        nonisolated(unsafe) var recordedMessages = [MethodParameters]()
         let methodObserving = messages.subscribe(onNext: { n in
             stages.append(.methodInvoked)
             recordedMessages.append(n)
@@ -860,12 +860,12 @@ extension SentMessageTest {
 
 extension SentMessageTest {
     func testMessageSentSubjectHasPublishBehavior() {
-        var messages: Observable<MethodParameters>!
-        var recordedMessages = [MethodParameters]()
-        var completed = false
+        nonisolated(unsafe) var messages: Observable<MethodParameters>!
+        nonisolated(unsafe) var recordedMessages = [MethodParameters]()
+        nonisolated(unsafe) var completed = false
         let disposeBag = DisposeBag()
 
-        var stages: [MessageProcessingStage] = []
+        nonisolated(unsafe) var stages: [MessageProcessingStage] = []
 
         autoreleasepool {
             let target = SentMessageTest_shared()
@@ -894,12 +894,12 @@ extension SentMessageTest {
     }
 
     func testInvokedMethodSubjectHasPublishBehavior() {
-        var messages: Observable<MethodParameters>!
-        var recordedMessages = [MethodParameters]()
-        var completed = false
+        nonisolated(unsafe) var messages: Observable<MethodParameters>!
+        nonisolated(unsafe) var recordedMessages = [MethodParameters]()
+        nonisolated(unsafe) var completed = false
         let disposeBag = DisposeBag()
 
-        var stages: [MessageProcessingStage] = []
+        nonisolated(unsafe) var stages: [MessageProcessingStage] = []
 
         autoreleasepool {
             let target = SentMessageTest_shared()
@@ -928,15 +928,15 @@ extension SentMessageTest {
     }
 
     func testDeallocSubjectHasReplayBehavior1() {
-        var deallocSequence: Observable<MethodParameters>!
+        nonisolated(unsafe) var deallocSequence: Observable<MethodParameters>!
         autoreleasepool {
             let target = SentMessageTest_shared()
 
             deallocSequence = target.rx.sentMessage(NSSelectorFromString("dealloc"))
         }
 
-        var called = false
-        var completed = false
+        nonisolated(unsafe) var called = false
+        nonisolated(unsafe) var completed = false
         _ = deallocSequence.subscribe(onNext: { n in
             called = true
         }, onCompleted: {
@@ -948,15 +948,15 @@ extension SentMessageTest {
     }
 
     func testDeallocSubjectHasReplayBehavior2() {
-        var deallocSequence: Observable<()>!
+        nonisolated(unsafe) var deallocSequence: Observable<()>!
         autoreleasepool {
             let target = SentMessageTest_shared()
 
             deallocSequence = target.rx.deallocating
         }
 
-        var called = false
-        var completed = false
+        nonisolated(unsafe) var called = false
+        nonisolated(unsafe) var completed = false
         _ = deallocSequence.subscribe(onNext: { n in
             called = true
         }, onCompleted: {
@@ -1182,9 +1182,9 @@ extension SentMessageTest {
     func testObservingForAllTypes() {
         let object = SentMessageTest_all_supported_types()
 
-        let closure: () -> Void = {  }
+        let closure: @Sendable () -> Void = {  }
 
-        let constChar = ("you better be listening" as NSString).utf8String!
+        nonisolated(unsafe) let constChar = ("you better be listening" as NSString).utf8String!
 
         let largeStruct = some_insanely_large_struct(a: (0, 1, 2, 3, 4, 5, 6, 7), some_large_text: nil, next: nil)
 
@@ -1287,7 +1287,7 @@ extension SentMessageTest {
 
     }
 
-    func _testMessageRecordedAndAllCallsAreMade<Result: Equatable>(_ selector: Selector, sendMessage: @escaping (SentMessageTest_all_supported_types) -> Result, expectedResult: Result) {
+    func _testMessageRecordedAndAllCallsAreMade<Result: Equatable>(_ selector: Selector, sendMessage: @escaping @Sendable (SentMessageTest_all_supported_types) -> Result, expectedResult: Result) {
         _testMessageRecordedAndAllCallsAreMade(selector, sendMessage: sendMessage, expectedResult: expectedResult) { target, selector in
             return ObservedSequence.sentMessage(target.rx.sentMessage(selector))
         }
@@ -1296,15 +1296,15 @@ extension SentMessageTest {
         }
     }
 
-    func _testMessageRecordedAndAllCallsAreMade<Result: Equatable>(_ selector: Selector, sendMessage: @escaping (SentMessageTest_all_supported_types) -> Result, expectedResult: Result, methodSelector: @escaping (SentMessageTest_all_supported_types, Selector) -> ObservedSequence) {
-        var observedMessages = [[Any]]()
-        var receivedDerivedClassMessage = [[Any]]()
-        var receivedBaseClassMessage = [[Any]]()
-        var completed = false
+    func _testMessageRecordedAndAllCallsAreMade<Result: Equatable>(_ selector: Selector, sendMessage: @escaping @Sendable (SentMessageTest_all_supported_types) -> Result, expectedResult: Result, methodSelector: @escaping @Sendable (SentMessageTest_all_supported_types, Selector) -> ObservedSequence) {
+        nonisolated(unsafe) var observedMessages = [[Any]]()
+        nonisolated(unsafe) var receivedDerivedClassMessage = [[Any]]()
+        nonisolated(unsafe) var receivedBaseClassMessage = [[Any]]()
+        nonisolated(unsafe) var completed = false
 
-        var result: Result! = nil
+        nonisolated(unsafe) var result: Result! = nil
 
-        var stages: [MessageProcessingStage] = []
+        nonisolated(unsafe) var stages: [MessageProcessingStage] = []
         
         let action: () -> Disposable = { () -> Disposable in
             let target = SentMessageTest_all_supported_types()
@@ -1350,12 +1350,12 @@ extension SentMessageTest {
      results properly can cause serious memory leaks.
     */
     func ensureGlobalRuntimeChangesAreCached<T: SentMessageTestClassCreationProtocol & NSObjectProtocol>(
-        _ createIt: @escaping () -> T,
-        observeIt: @escaping (T) -> [ObservedSequence],
+        _ createIt: @escaping @Sendable () -> T,
+        observeIt: @escaping @Sendable (T) -> [ObservedSequence],
         objectActingClassChange: [ObjectRuntimeChange],
         objectRealClassChange: [ObjectRuntimeChange],
         runtimeChange: RxObjCRuntimeChange,
-        useIt: @escaping (T) -> [[MethodParameters]]
+        useIt: @escaping @Sendable (T) -> [[MethodParameters]]
         ) {
         // First run normal experiment
         _ensureGlobalRuntimeChangesAreCached(createIt,
@@ -1392,12 +1392,12 @@ extension SentMessageTest {
 
         let originalRuntimeState = RxObjCRuntimeState()
 
-        var createdObject: T! = nil
-        var disposables = [Disposable]()
+        nonisolated(unsafe) var createdObject: T! = nil
+        nonisolated(unsafe) var disposables = [Disposable]()
 
-        var nCompleted = 0
-        var recordedParameters = [[MethodParameters]]()
-        var observables: [ObservedSequence] = []
+        nonisolated(unsafe) var nCompleted = 0
+        nonisolated(unsafe) var recordedParameters = [[MethodParameters]]()
+        nonisolated(unsafe) var observables: [ObservedSequence] = []
 
         autoreleasepool {
             createdObject = createIt()
@@ -1420,9 +1420,9 @@ extension SentMessageTest {
         )
         afterObserveRuntimeState.assertAfterThisMoment(originalRuntimeState, changed: runtimeChange)
 
-        var messageProcessingStage: [MessageProcessingStage] = []
+        nonisolated(unsafe) var messageProcessingStage: [MessageProcessingStage] = []
         autoreleasepool {
-            var i = 0
+            nonisolated(unsafe) var i = 0
 
             for o in observables {
                 let index = i
@@ -1439,7 +1439,7 @@ extension SentMessageTest {
             }
         }
 
-        var invokedCount = 0
+        nonisolated(unsafe) var invokedCount = 0
         createdObject.invokedMethod = {
             messageProcessingStage.append(.invoking)
             invokedCount = invokedCount + 1
@@ -1491,7 +1491,7 @@ extension SentMessageTest {
 
     }
 
-    func createKVODynamicSubclassed<T: SentMessageTestClassCreationProtocol & NSObjectProtocol>(_ type: T.Type = T.self) -> () -> (T, [Disposable]) {
+    func createKVODynamicSubclassed<T: SentMessageTestClassCreationProtocol & NSObjectProtocol>(_ type: T.Type = T.self) -> @Sendable () -> (T, [Disposable]) {
         return {
             let t = T.createInstance()
             //let disposable = (t as! NSObject).rx.observe(NSArray.self, "messages").publish().connect()
@@ -1500,7 +1500,7 @@ extension SentMessageTest {
         }
     }
 
-    func createNormalInstance<T: SentMessageTestClassCreationProtocol & NSObjectProtocol>(_ type: T.Type = T.self) -> () -> T {
+    func createNormalInstance<T: SentMessageTestClassCreationProtocol & NSObjectProtocol>(_ type: T.Type = T.self) -> @Sendable () -> T {
         return {
             return T.createInstance()
         }
diff --git a/Tests/RxCocoaTests/SharedSequence+Test.swift b/Tests/RxCocoaTests/SharedSequence+Test.swift
index e2406f477..217f2f2df 100644
--- a/Tests/RxCocoaTests/SharedSequence+Test.swift
+++ b/Tests/RxCocoaTests/SharedSequence+Test.swift
@@ -26,9 +26,9 @@ class SharedSequenceTest: RxTest {
 // * events are observed on main thread - observe(on:MainScheduler.instance)
 // * it can't error out - it needs to have catch somewhere
 extension SharedSequenceTest {
-    func subscribeTwiceOnBackgroundSchedulerAndOnlyOneSubscription<Result, S>(_ xs: SharedSequence<S, Result>, expectationFulfilled: @escaping (Result) -> Bool = { _ in false }, subscribedOnBackground: () -> Void) -> [Result] {
-        var firstElements = [Result]()
-        var secondElements = [Result]()
+    func subscribeTwiceOnBackgroundSchedulerAndOnlyOneSubscription<Result, S>(_ xs: SharedSequence<S, Result>, expectationFulfilled: @escaping @Sendable (Result) -> Bool = { _ in false }, subscribedOnBackground: () -> Void) -> [Result] {
+        nonisolated(unsafe) var firstElements = [Result]()
+        nonisolated(unsafe) var secondElements = [Result]()
 
         let subscribeFinished = self.expectation(description: "subscribeFinished")
 
diff --git a/Tests/RxSwiftTests/RecursiveLockTest.swift b/Tests/RxSwiftTests/RecursiveLockTest.swift
index 37061a29e..8e9ecf0a0 100644
--- a/Tests/RxSwiftTests/RecursiveLockTest.swift
+++ b/Tests/RxSwiftTests/RecursiveLockTest.swift
@@ -16,9 +16,9 @@ import XCTest
 #endif
 
 private class StrandClosure {
-    let closure: () -> Void
+    let closure: @Sendable () -> Void
 
-    init(closure: @escaping () -> Void) {
+    init(closure: @escaping @Sendable () -> Void) {
       self.closure = closure
     }
 }
@@ -53,7 +53,7 @@ class RecursiveLockTests: RxTest {
 
     // code taken from https://github.com/ketzusaka/Strand/blob/master/Sources/Strand.swift
 
-    func thread(action: @escaping () -> ()) {
+    func thread(action: @escaping @Sendable () -> ()) {
         let holder = Unmanaged.passRetained(StrandClosure(closure: action))
         let pointer = UnsafeMutableRawPointer(holder.toOpaque())
         #if os(Linux)
diff --git a/Tests/RxSwiftTests/SharingSchedulerTests.swift b/Tests/RxSwiftTests/SharingSchedulerTests.swift
index ea36bfd4a..10e48a7b3 100644
--- a/Tests/RxSwiftTests/SharingSchedulerTests.swift
+++ b/Tests/RxSwiftTests/SharingSchedulerTests.swift
@@ -69,15 +69,15 @@ class Scheduler1: SchedulerType {
         fatalError()
     }
 
-    func schedule<StateType>(_ state: StateType, action: @escaping (StateType) -> Disposable) -> Disposable {
+    func schedule<StateType>(_ state: StateType, action: @escaping @Sendable (StateType) -> Disposable) -> Disposable {
         fatalError()
     }
 
-    func scheduleRelative<StateType>(_ state: StateType, dueTime: RxTimeInterval, action: @escaping (StateType) -> Disposable) -> Disposable {
+    func scheduleRelative<StateType>(_ state: StateType, dueTime: RxTimeInterval, action: @escaping @Sendable (StateType) -> Disposable) -> Disposable {
         fatalError()
     }
 
-    func schedulePeriodic<StateType>(_ state: StateType, startAfter: RxTimeInterval, period: RxTimeInterval, action: @escaping (StateType) -> StateType) -> Disposable {
+    func schedulePeriodic<StateType>(_ state: StateType, startAfter: RxTimeInterval, period: RxTimeInterval, action: @escaping @Sendable (StateType) -> StateType) -> Disposable {
         fatalError()
     }
 }
@@ -87,15 +87,15 @@ class Scheduler2: SchedulerType {
         fatalError()
     }
 
-    func schedule<StateType>(_ state: StateType, action: @escaping (StateType) -> Disposable) -> Disposable {
+    func schedule<StateType>(_ state: StateType, action: @escaping @Sendable (StateType) -> Disposable) -> Disposable {
         fatalError()
     }
 
-    func scheduleRelative<StateType>(_ state: StateType, dueTime: RxTimeInterval, action: @escaping (StateType) -> Disposable) -> Disposable {
+    func scheduleRelative<StateType>(_ state: StateType, dueTime: RxTimeInterval, action: @escaping @Sendable (StateType) -> Disposable) -> Disposable {
         fatalError()
     }
 
-    func schedulePeriodic<StateType>(_ state: StateType, startAfter: RxTimeInterval, period: RxTimeInterval, action: @escaping (StateType) -> StateType) -> Disposable {
+    func schedulePeriodic<StateType>(_ state: StateType, startAfter: RxTimeInterval, period: RxTimeInterval, action: @escaping @Sendable (StateType) -> StateType) -> Disposable {
         fatalError()
     }
 }
diff --git a/Tests/XCTest+AllTests.swift b/Tests/XCTest+AllTests.swift
index cc54f5dd2..c478981aa 100644
--- a/Tests/XCTest+AllTests.swift
+++ b/Tests/XCTest+AllTests.swift
@@ -80,10 +80,10 @@ func XCTAssertArraysEqual<T>(_ lhs: [T], _ rhs: [T], file: StaticString = #file,
 }
 
 
-func doOnBackgroundQueue(_ action: @escaping () -> Void) {
+func doOnBackgroundQueue(_ action: @escaping @Sendable () -> Void) {
     DispatchQueue.global(qos: .default).async(execute: action)
 }
 
-func doOnMainQueue(_ action: @escaping () -> Void) {
+func doOnMainQueue(_ action: @escaping @Sendable () -> Void) {
     DispatchQueue.main.async(execute: action)
 }