code: public Observable<Page<UserSubscriptionQuotaInner>> listAsync() {
          return listWithServiceResponseAsync().map(new Func1<ServiceResponse<List<UserSubscriptionQuotaInner>>, Page<UserSubscriptionQuotaInner>>() {
              @Override
              public Page<UserSubscriptionQuotaInner> call(ServiceResponse<List<UserSubscriptionQuotaInner>> response) {
                  PageImpl1<UserSubscriptionQuotaInner> page = new PageImpl1<>();
                  page.setItems(response.body());
                  return page;
              }
          });
      }
docs: Get the number of iot hubs in the subscription.
  Get the number of free and paid iot hubs in the subscription.
  
  @return the observable to the List&lt;UserSubscriptionQuotaInner&gt; object