anchor.diff:    double volume = 1.0;
     double pitch = 1.0;
     double pan = 0.0;
  -  Object tag;
   
     // TODO: Implement completion callback. On completion, sounds should
     // also be removed from the list of playing sounds.
  
positive.code:         playingSound._player.ptr.start();
        });
  
        _playingSounds.add(playingSound);
        _mediaPlayers[sound] = playingSound._player;
      } else {
        // Reuse player
  
negative.code: class SoundEffectStream {
    SoundEffectStream(
      this.sound,
      this.loop,
      this.volume,
      this.pitch,
  