Add OnError for SocketException

[imerr]

On windows, when trying to connect to localhost, there seems to be an edge case where instead of timing out or anything like that, windows knows better and raises a socket exception here: "System.Net.Sockets.SocketException (0x80004005): An existing connection was forcibly closed by the remote host.", which of course doesnt make any sense whatsoever if there's not a server listening to begin with (should be a connection refused really), but thats how it is