MINOR: mux-h1: Rework how shutdowns are handled

We now only rely on one flag to notify a shutdown. The shutdown is performed
at the connection level when there are no more pending outgoing data. So, it
means it is performed immediately if the output buffer is empty. Otherwise
it is deferred after the outgoing data are sent.

This simplify a bit the mux because there is now only one flag to check.
1 file changed