Handle SocketError.Shutdown.

Signed-off-by: Miguel Labayen <[email protected]>

Author: Miguel Labayen

src/NetMQ/Core/Transports/StreamEngine.cs

@@ -1049,7 +1049,8 @@ private static int EndWrite(SocketError socketError, int bytesTransferred)
                 socketError == SocketError.ConnectionAborted ||
                 socketError == SocketError.TimedOut ||
                 socketError == SocketError.ConnectionReset ||
-                socketError == SocketError.AccessDenied)
+                socketError == SocketError.AccessDenied || 
+                socketError == SocketError.Shutdown)
                 return -1;
 
             throw NetMQException.Create(socketError);