code: public TopicInner update(String resourceGroupName, String topicName, Map<String, String> tags) {
          return updateWithServiceResponseAsync(resourceGroupName, topicName, tags).toBlocking().last().body();
      }
docs: Update a topic.
  Asynchronously updates a topic with the specified parameters.
  
  @param resourceGroupName The name of the resource group within the user's subscription.
  @param topicName Name of the topic
  @param tags Tags of the resource
  @throws IllegalArgumentException thrown if parameters fail the validation
  @throws CloudException thrown if the request is rejected by server
  @throws RuntimeException all other wrapped checked exceptions if the request fails to be sent
  @return the TopicInner object if successful.