code: public Timer add(long interval, TimerHandler handler, Object... args)
      {
          if (handler == null) {
              return null;
          }
          return new Timer(timer.add(interval, handler, args));
      }
docs: Add timer to the set, timer repeats forever, or until cancel is called.
  @param interval the interval of repetition in milliseconds.
  @param handler the callback called at the expiration of the timer.
  @param args the optional arguments for the handler.
  @return an opaque handle for further cancel.