code: public DomainTopicInner get(String resourceGroupName, String domainName, String topicName) {
          return getWithServiceResponseAsync(resourceGroupName, domainName, topicName).toBlocking().single().body();
      }
docs: Get a domain topic.
  Get properties of a domain topic.
  
  @param resourceGroupName The name of the resource group within the user's subscription.
  @param domainName Name of the domain
  @param topicName Name of the topic
  @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 DomainTopicInner object if successful.