FlushClient() does drops the output buffer, when it becomes empty.
This previously wasn't any problem and actually intented, because we've
returned from the write path directly after FlushClient() was called.
But now we've changed the call order, so it's called from within
OutputBufferMakeRoom(), so we need to make sure we always got valid
output buffer before trying to access it.
For the future, we should think about whether dropping output buffers
really makes sense at all. Instead we could leave them as they are
(over the client's lifetime) and maybe just trim when they've went
too big.
Fixes: 1c13cfa6ca
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
435de433cd