title: A non-blocking socket operation could not be completed immediately on send
body: <p>I'm writing a server for a game, and I want to be able to handle thousands of concurrent users.  For this reason, I went with non-blocking sockets and use the poll method.  However, I do create multiple threads to handle database and web calls, and some of these threads will send a response to the user.  In one of these threads, on send, I get the error "A non-blocking socket operation could not be completed immediately".  What could cause this problem?  I imagine it's because a poll is occurring at the same time as send is called.  If I used beginAsync, would it take stop this error?  I thought about locking the socket, but I don't want my main thread to be blocked for this.</p>