code: private String getElapsedTimeLabel(long elapsed) {
          return (elapsed >= 0) ?
                  String.format("%02d:%02d.%03d", elapsed / 60000, (elapsed % 60000) / 1000, (elapsed % 1000)) :
                  null;
      }
docs: Inner method for elapsed time label formatting
  @param elapsed the time in milliseconds
  @return the label with the elapsed time in readable format