public Set<String> getTopicsSubscribedByConsumer(final String consumerId) {
    final Set<String> topics = new HashSet<>();
    for (final Map.Entry<String, Set<String>> topicNameToSubscribedConsumerId :
        topicNameToSubscribedConsumerIdSet.entrySet()) {
      if (topicNameToSubscribedConsumerId.getValue().contains(consumerId)) {
        topics.add(topicNameToSubscribedConsumerId.getKey());
      }
    }
    return topics;
  }
Get the consumers subscribing the given topic in this group.

@param topic The topic name.
@return The set of consumer IDs subscribing the given topic in this group. If no consumer is
    subscribing the topic, return an empty set.
iotdb-core/node-commons/src/main/java/org/apache/iotdb/commons/subscription/meta/consumer/ConsumerGroupMeta.java