code: @Nullable
      public static TtlTimerTask get(@Nullable TimerTask timerTask) {
          return get(timerTask, false, false);
      }
docs: Factory method, wrap input {@link TimerTask} to {@link TtlTimerTask}.
  <p>
  This method is idempotent.
  
  @param timerTask input {@link TimerTask}
  @return Wrapped {@link TimerTask}