When draining the socket in IServerConnection, we would previously
handle each incoming (local endpoint) message as it came in.
This would cause unexpected things to happen while blocked waiting
for a synchronous response. That's definitely not what we want,
so this patch puts all of the incoming messages in a queue and does
a separate pass over the queue to handle everything in order.
This matches what we're already calling the server-side subclasses
better, though we'll probably want to find some better names for the
client-side classes eventually.
