Fix packet instantiation on 1.20.6

src/main/java/com/comphenix/protocol/injector/StructureCache.java

@@ -54,6 +54,16 @@
  * @author Kristian
  */
 public class StructureCache {
+	private static final sun.misc.Unsafe UNSAFE;
+	static {
+		try {
+			java.lang.reflect.Field f = sun.misc.Unsafe.class.getDeclaredField("theUnsafe");
+			f.setAccessible(true);
+			UNSAFE = (sun.misc.Unsafe) f.get(null);
+		} catch (NoSuchFieldException | IllegalAccessException e) {
+			throw new RuntimeException(e);
+		}
+	}
 
     // Structure modifiers
     private static final Map<Class<?>, Supplier<Object>> PACKET_INSTANCE_CREATORS = new ConcurrentHashMap<>();
@@ -91,6 +101,19 @@ public static Object newPacket(Class<?> packetClass) {
 						// shrug, fall back to default behaviour
 					}
 				}
+
+				try {
+					UNSAFE.allocateInstance(packetClass);
+					return () -> {
+						try {
+							return UNSAFE.allocateInstance(packetClass);
+						} catch (InstantiationException e) {
+							throw new RuntimeException(e);
+						}
+					};
+				} catch (Exception ignored) {
+					// shrug, fall back to default behaviour
+				}
 			}
 
             // prefer construction via PacketDataSerializer constructor on 1.17 and above

src/main/java/com/comphenix/protocol/injector/packet/PacketRegistry.java

@@ -461,7 +461,10 @@ private static synchronized Register createRegisterV1_20_5() {
 						}
 
 						Object serializer = idCodecEntrySerializerAccessor.invoke(entry);
-						result.classToCodec.put(packetClass, new WrappedStreamCodec(serializer));
+						Field outerThisField = serializer.getClass().getDeclaredField("this$0");
+						outerThisField.setAccessible(true);
+						Object realSer = outerThisField.get(serializer);
+						result.classToCodec.put(packetClass, new WrappedStreamCodec(realSer));
 					}
 
 					// get EnumProtocol and Direction of protocol info