rx-transformers-doOnLast.java

 public static <T> Observable.Transformer<T, T> doOnLast(Action1<T> doOnCompleteFunc) {
    return new Observable.Transformer<T, T>() {
      private T lastValue;

      @Override
      public Observable<T> call(Observable<T> observable) {
        return observable.doOnNext(value -> {
          lastValue = value;
        }).doOnCompleted(() -> {
          doOnCompleteFunc.call(lastValue);
        });
      }
    };
  }