anchor.diff:  
     factory AssetsAudioPlayer.newPlayer() => _getOrCreate(id: uuid.v4());
   
  -  final AudioPlayerHandler audioPlayerHandler;
  +  AudioPlayerHandler audioPlayerHandler;
   
     /// empty constructor now create a new player
     factory AssetsAudioPlayer() => AssetsAudioPlayer.newPlayer();
  
positive.code: 
    final String id;
  
    AssetsAudioPlayer._({this.audioPlayerHandler, this.id = _DEFAULT_PLAYER}) {
      _init();
    }
  
  
negative.code:     if (_players.containsKey(id)) {
        return _players[id];
      } else {
        final player = AssetsAudioPlayer._(
          id: id,
        );
        _players[id] = player;
        return player;
      }
  