code: @SuppressWarnings("unchecked")
      public Set<String> getTopics() {
          Map<String, List<PartitionInfo>> topicInfo = getTopicInfo();
          Set<String> topics = topicInfo != null ? topicInfo.keySet() : null;
          return topics != null ? Collections.unmodifiableSet(topics) : Collections.EMPTY_SET;
      }
docs: Gets all available topics.
  
  @return
  @since 1.3.0