code: public PubsubFuture<Topic> getTopic(final String project, final String topic) {
      return getTopic(canonicalTopic(project, topic));
    }
docs: Get a Pub/Sub topic.
  
  @param project The Google Cloud project.
  @param topic   The name of the topic to get.
  @return A future that is completed when this request is completed. The future will be completed with {@code null}
  if the response is 404.