The graph cycle goes: driver timeout -> process output nodes -> process
driver node. Hence, driver should produce buffers in the timeout,
otherwise there's one quantum extra latency.
Make the bluez5 media/sco sources as drivers put a buffer to io before
indicating ready, and as follower do it in process. Also make checks if
io == NULL, and don't set io->status to HAVE_DATA unless there really is
a buffer ready.
Driver timeouts need to be started/stopped when we switch from follower
to driver or vice versa.
The BT sources fail to do this, so fix it. Sinks already do it right.
For backward compatibility with old Wireplumber releases, support the
old api.bluez5.a2dp.sink/source names, and use them in object events
instead of the media.sink/source names.
We can't determine which remote endpoint or device the
SelectConfiguration() call is associated with. For LE Audio BAP, as this
method is called only for the Initiator we set the whole instance as a
Central/Initiator.
This flag is unset on BAP media endpoint removal.
