If we issue a short write, libwebsocket handles it kinda ungracefully and we have no idea when to close the socket. Instead of letting libwebsocket copy our content into a temporary buffer, we can just give it smaller pieces.

This keeps the size of the fcserver binary down.

This is really dumb, we weren't processing backlogged packets from the opcsink buffer. This is the cause of the ugly delays I'd been seeing in the 'waves' demo.