code: public synchronized void clearPlaybackState(int player) {
          PlaybackState oldFurthestState = getFurthestPlaybackState();
          PlaybackState oldState = playbackStateMap.remove(player);
          repaintDueToPlaybackStateChange(oldState, null, oldFurthestState);
      }
docs: Clear the playback state stored for a player, such as when it has unloaded the track.
  
  @param player the player number whose playback state is no longer valid
  @since 0.5.0