Finalizer thread blocked if ZmqContext goes out of scope

[rtanase]

Hi,

If we're not careful to dispose the ZmqSockets created and the ZmqContext goes out of scope, the finalizer thread is stuck forever. The documentation says that we're supposed to use a non-default Linger setting to make sure sockets would not stay blocked, but even with that option I'm still unable to avoid the blocking on the finalizer.

A simple repro is here:

var context = ZmqContext.Create();
var socket = context.CreateSocket(SocketType.PUB);
socket.Identity = Guid.NewGuid().ToByteArray();
socket.Linger = TimeSpan.FromSeconds(1);
socket.TcpKeepalive = TcpKeepaliveBehaviour.Enable;
context = null;
GC.Collect();
GC.WaitForPendingFinalizers();

[fynman]

add socket.Close() before context = null