code: private PubsubFuture<Topic> createTopic(final String canonicalTopic) {
      validateCanonicalTopic(canonicalTopic);
      return put("create topic", canonicalTopic, NO_PAYLOAD, readJson(Topic.class));
    }
docs: Create a Pub/Sub topic.
  
  @param canonicalTopic The canonical (including project) name of the topic to create.
  @return A future that is completed when this request is completed.