code: public Observable<ServiceResponse<Page<SharedAccessSignatureAuthorizationRuleInner>>> listKeysWithServiceResponseAsync(final String resourceGroupName, final String resourceName) {
          return listKeysSinglePageAsync(resourceGroupName, resourceName)
              .concatMap(new Func1<ServiceResponse<Page<SharedAccessSignatureAuthorizationRuleInner>>, Observable<ServiceResponse<Page<SharedAccessSignatureAuthorizationRuleInner>>>>() {
                  @Override
                  public Observable<ServiceResponse<Page<SharedAccessSignatureAuthorizationRuleInner>>> call(ServiceResponse<Page<SharedAccessSignatureAuthorizationRuleInner>> page) {
                      String nextPageLink = page.body().nextPageLink();
                      if (nextPageLink == null) {
                          return Observable.just(page);
                      }
                      return Observable.just(page).concatWith(listKeysNextWithServiceResponseAsync(nextPageLink));
                  }
              });
      }
docs: Get the security metadata for an IoT hub. For more information, see: https://docs.microsoft.com/azure/iot-hub/iot-hub-devguide-security.
  Get the security metadata for an IoT hub. For more information, see: https://docs.microsoft.com/azure/iot-hub/iot-hub-devguide-security.
  
  @param resourceGroupName The name of the resource group that contains the IoT hub.
  @param resourceName The name of the IoT hub.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the PagedList&lt;SharedAccessSignatureAuthorizationRuleInner&gt; object