playbackState property
A controller for broadcasting the current PlaybackState
to the app's UI,
media notification and other clients. Example usage:
playbackState.add(playbackState.value!.copyWith(playing: true));
The state changes broadcast via this stream can be listened to via the Flutter app's UI
Implementation
@override
// ignore: close_sinks
final BehaviorSubject<PlaybackState> playbackState =
BehaviorSubject.seeded(PlaybackState());