code: public <T> void restartableFirst(int restartableId, final Func0<Observable<T>> observableFactory,
          final Action2<View, T> onNext, @Nullable final Action2<View, Throwable> onError) {
  
          restartable(restartableId, new Func0<Subscription>() {
              @Override
              public Subscription call() {
                  return observableFactory.call()
                      .compose(RxPresenter.this.<T>deliverFirst())
                      .subscribe(split(onNext, onError));
              }
          });
      }
docs: This is a shortcut that can be used instead of combining together
  {@link #restartable(int, Func0)},
  {@link #deliverFirst()},
  {@link #split(Action2, Action2)}.
  
  @param restartableId     an id of the restartable.
  @param observableFactory a factory that should return an Observable when the restartable should run.
  @param onNext            a callback that will be called when received data should be delivered to view.
  @param onError           a callback that will be called if the source observable emits onError.
  @param <T>               the type of the observable.