With subscription manager, there is no need to tell a publisher
about a subscriber going away. Before subscription manager,
the up track manager of a participant (i. e. the publisher side)
was holding a list of pending subscriptions for its published tracks
and that had to be cleaned up if one of the subscriber goes away.
That is not the case any more.
Also set publisherID early so that subscription permission update has
the right publisherID. In fact, saw an empty ID in the logs and saw
that we still have the disallowed subscription handling which is not
necessary any more.
UpdateSubscription had a shortcoming where when it couldn't find the
participant, it ignored the request.
This PR further removes the reliance of current publisher state from
subscribers.
- SubscribeToTrack only takes in a trackID
- Introduced RoomTrackManager to maintain all published tracks to a room
- Added TrackUnpublished event to clearly indicate when a track has been removed
- SubscribeRequested event no longer include information about the publisher
* Return early if already subscribed.
When already subscribed, returned `subTrack` is nil.
Return early, but do not return an error.
* check for nil subTrack
* check for nil as well
Added a new manager to handle all subscription needs. Implemented using reconciler pattern. The goals are:
improve subscription resilience by separating desired state and current state
reduce complexity of synchronous processing
better detect failures with the ability to trigger full reconnect
Raja Subramanian