The note that tells the model the user turned a source off:
"[You can no longer see: Whiteboard (the user turned it off)]". A call's video source arbiter sends it when the user
turns a source off.
Parameters
sourceLabel: string
The source's human-readable name, put in as given.
The note that tells the model the user turned a source off: "[You can no longer see: Whiteboard (the user turned it off)]". A call's video source arbiter sends it when the user turns a source off.