docs: public Observable<List<EventSubscriptionInner>> listByDomainTopicAsync(String resourceGroupName, String domainName, String topicName) {
          return listByDomainTopicWithServiceResponseAsync(resourceGroupName, domainName, topicName).map(new Func1<ServiceResponse<List<EventSubscriptionInner>>, List<EventSubscriptionInner>>() {
              @Override
              public List<EventSubscriptionInner> call(ServiceResponse<List<EventSubscriptionInner>> response) {
                  return response.body();
              }
          });
      }