I've been looking into some of the issues about allowing the socket's kernel buffer to run out of space, and was wondering why not simply remove MSG_DONTWAIT from the sendmsg call in wl_connection_flush? That should implement flow control by having the sender thread wait until the receiver has emptied the socket's buffer sufficiently.
It seems to me that using an unbounded buffer could cause memory resource problems on whichever end was using that buffer. Was removing MSG_DONTWAIT from the sendmsg call considered and abandoned for some reason?
