code: public static <InnerT> Observable<InnerT> convertPageToInnerAsync(Observable<Page<InnerT>> innerPage) {
          return innerPage.flatMap(new Func1<Page<InnerT>, Observable<InnerT>>() {
              @Override
              public Observable<InnerT> call(Page<InnerT> pageInner) {
                  return Observable.from(pageInner.items());
              }
          });
      }
docs: Converts Observable of page to Observable of Inner.
  @param <InnerT> type of inner.
  @param innerPage Page to be converted.
  @return Observable for list of inner.