Keep track of the current quantum and recalculate the tlength in the
same way that pulseaudio does.
Send a bufferattr changed message to a client when we change the
parameters.
This fixes the case where the quantum is increased and there needs to be
more buffering to keep the stream going.
When the client adapter is configured in passthrough mode, the stream param
changed event in pipewire-pulse is emitted before the session manager creates
the link, and not after. Therfore, the peer can never be found when replying
create stream, and the pulseaudio application receives a stream error.
This patch delays the create stream reply until the link is added if the peer
cannot be found, fixing the above race conditon to allow passthrough mode to
work with pulseaudio applications.