code: public Observable<ServiceResponse<IotHubDescriptionInner>> updateWithServiceResponseAsync(String resourceGroupName, String resourceName) {
          if (this.client.subscriptionId() == null) {
              throw new IllegalArgumentException("Parameter this.client.subscriptionId() is required and cannot be null.");
          }
          if (resourceGroupName == null) {
              throw new IllegalArgumentException("Parameter resourceGroupName is required and cannot be null.");
          }
          if (resourceName == null) {
              throw new IllegalArgumentException("Parameter resourceName is required and cannot be null.");
          }
          if (this.client.apiVersion() == null) {
              throw new IllegalArgumentException("Parameter this.client.apiVersion() is required and cannot be null.");
          }
          final Map<String, String> tags = null;
          TagsResource iotHubTags = new TagsResource();
          iotHubTags.withTags(null);
          Observable<Response<ResponseBody>> observable = service.update(this.client.subscriptionId(), resourceGroupName, resourceName, this.client.apiVersion(), this.client.acceptLanguage(), iotHubTags, this.client.userAgent());
          return client.getAzureClient().getPutOrPatchResultAsync(observable, new TypeToken<IotHubDescriptionInner>() { }.getType());
      }
docs: Update an existing IoT Hubs tags.
  Update an existing IoT Hub tags. to update other fields use the CreateOrUpdate method.
  
  @param resourceGroupName Resource group identifier.
  @param resourceName Name of iot hub to update.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable for the request