RoomlifecycleManager: Unsubscribe room monitoring as a part of room release

[sacOO7]

• Currently, Room monitoring is enabled for each feature using channel.on('update') and all other channel events.
• After setting status to RoomStatus.Released
  

  ably-chat-js/src/core/room-lifecycle-manager.ts

  Line 891 in 0e1b523

  this._lifecycle.setStatus({ status: RoomStatus.Released });

  .
  we should deregister all of those listeners using

    for (const feature of this._contributors) {
      feature.channel.offAll();
    }

┆Issue is synchronized with this Jira Task by Unito

[sacOO7]

Also, I am not sure whether we should turn off those listeners before we start with the Room.release operation.
i.e. After setting status to RoomStatus.Releasing, because I also feel room monitoring shouldn't interfere with room release process.

[AndyTWF]

All of the code blocks you point to have a check that causes them to effectively no-op if a release (or any other) operation is in progress. The only exception to this is checking for discontinuity.

[sacOO7]

Yeah, I agree they cause no-op after release ( I think we listen to detached/failed when release is happening ), but callbacks will still be a part of internal listeners after release and won't be garbage collected.
I think when Room goes into Released state, can remove those listeners.

[sacOO7]

• I believe we might like to unsubscribe to room monitoring listeners right before we set
  

  ably-chat-js/src/core/room-lifecycle-manager.ts

  Line 824 in 533c4d0

  this._lifecycle.setStatus({ status: RoomStatus.Releasing });

• Since we are commencing the Release operation, there's no point in listening to discontinuity events, or we emit discontinuity error for each feature specifying release operation in progress.

• Room release should emit Releasing and Released status which denotes end of current room lifeycle.

• Release mainly detach each channel. This will emit DETACHED or FAILED channel events and will be captured by room monitoring listeners.

• Although, we do nothing for Detached, for Failed channel event, we override Released room status with Failed room status as a part of room monitoring and start channel-WindDown again ( depending on how we set _operationInProgress flag -> [RoomLifeCycleManager] _operationInProgress flag incorrectly set #406 )
  

  ably-chat-js/src/core/room-lifecycle-manager.ts

  Lines 227 to 244 in 533c4d0

  	if (change.current === RoomStatus.Failed) {
  	this._logger.debug('RoomLifecycleManager(); detected channel failure', {
  	channel: contributor.channel.name,
  	});
  	this._clearAllTransientDetachTimeouts();
  	this._operationInProgress = true;
  	this._lifecycle.setStatus({
  	status: RoomStatus.Failed,
  	error: change.reason,
  	});
  	// We'll make a best effort at detaching all the other channels
  	this._doChannelWindDown(contributor).catch((error: unknown) => {
  	this._logger.error('RoomLifecycleManager(); failed to detach all channels following failure', {
  	contributor: contributor.channel.name,
  	error,
  	});
  	});

• We can also get rid of extra checks as per [CHA-RL3c][RoomLifecycle] Redundant _releaseInProgress check #399 (comment)