Use FDWatcher instead of _FDWatcher

This has a slightly more polished API.

src/ZMQ.jl

@@ -4,7 +4,7 @@ module ZMQ
 using ZeroMQ_jll
 
 using Base.Libc: EAGAIN
-using FileWatching: UV_READABLE, uv_pollcb, _FDWatcher
+using FileWatching: UV_READABLE, uv_pollcb, FDWatcher
 import Sockets
 using Sockets: connect, bind, send, recv
 import Base.GC: @preserve

src/comm.jl

@@ -16,7 +16,7 @@ function _send(socket::Socket, zmsg, more::Bool=false)
                 wait(socket)
             end
         else
-            notify_is_expensive = !isempty(getfield(socket,:pollfd).notify.waitq)
+            notify_is_expensive = !isempty(getfield(socket,:pollfd).watcher.notify.waitq)
             if notify_is_expensive
                 socket.events != 0 && notify(socket)
             end
@@ -80,7 +80,7 @@ function _recv!(socket::Socket, zmsg)
                 wait(socket)
             end
         else
-            notify_is_expensive = !isempty(getfield(socket,:pollfd).notify.waitq)
+            notify_is_expensive = !isempty(getfield(socket,:pollfd).watcher.notify.waitq)
             if notify_is_expensive
                 socket.events != 0 && notify(socket)
             end

src/socket.jl

@@ -19,7 +19,7 @@ Do-block constructor.
 """
 mutable struct Socket
     data::Ptr{Cvoid}
-    pollfd::_FDWatcher
+    pollfd::FDWatcher
 
     """
         Socket(ctx::Context, typ::Integer)
@@ -32,7 +32,7 @@ mutable struct Socket
             throw(StateError(jl_zmq_error_str()))
         end
         socket = new(p)
-        setfield!(socket, :pollfd, _FDWatcher(fd(socket), #=readable=#true, #=writable=#false))
+        setfield!(socket, :pollfd, FDWatcher(fd(socket), #=readable=#true, #=writable=#false))
         finalizer(close, socket)
         push!(getfield(ctx, :sockets), WeakRef(socket))
         return socket
@@ -72,7 +72,7 @@ Base.isopen(socket::Socket) = getfield(socket, :data) != C_NULL
 """
 function Base.close(socket::Socket)
     if isopen(socket)
-        close(getfield(socket, :pollfd), #=readable=#true, #=writable=#false)
+        close(getfield(socket, :pollfd))
         rc = ccall((:zmq_close, libzmq), Cint,  (Ptr{Cvoid},), socket)
         setfield!(socket, :data, C_NULL)
         if rc != 0
@@ -90,8 +90,8 @@ if Sys.iswindows()
     Base.fd(socket::Socket) = WindowsRawSocket(convert(Ptr{Cvoid}, socket.fd))
 end
 
-Base.wait(socket::Socket) = wait(getfield(socket, :pollfd), readable=true, writable=false)
-Base.notify(socket::Socket) = @preserve socket uv_pollcb(getfield(socket, :pollfd).handle, Int32(0), Int32(UV_READABLE))
+Base.wait(socket::Socket) = wait(getfield(socket, :pollfd))
+Base.notify(socket::Socket) = @preserve socket uv_pollcb(getfield(socket, :pollfd).watcher.handle, Int32(0), Int32(UV_READABLE))
 
 """
     Sockets.bind(socket::Socket, endpoint::AbstractString)