code: @CheckReturnValue
      @SchedulerSupport(SchedulerSupport.NONE)
      public final Maybe<T> doOnComplete(Action onComplete) {
          return RxJavaPlugins.onAssembly(new MaybePeek<T>(this,
                  Functions.emptyConsumer(), // onSubscribe
                  Functions.emptyConsumer(), // onSuccess
                  Functions.emptyConsumer(), // onError
                  ObjectHelper.requireNonNull(onComplete, "onComplete is null"),
                  Functions.EMPTY_ACTION,    // (onSuccess | onError | onComplete)
                  Functions.EMPTY_ACTION     // dispose
          ));
      }
docs: Modifies the source Maybe so that it invokes an action when it calls {@code onComplete}.
  <p>
  <img width="640" height="358" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/doOnComplete.m.png" alt="">
  <dl>
  <dt><b>Scheduler:</b></dt>
  <dd>{@code doOnComplete} does not operate by default on a particular {@link Scheduler}.</dd>
  </dl>
  
  @param onComplete
  the action to invoke when the source Maybe calls {@code onComplete}
  @return the new Maybe with the side-effecting behavior applied
  @see <a href="http://reactivex.io/documentation/operators/do.html">ReactiveX operators documentation: Do</a>