@Override
  public boolean equals(final Object obj) {
    if (this == obj) {
      return true;
    }
    if (obj == null || getClass() != obj.getClass()) {
      return false;
    }
    final TopicMeta that = (TopicMeta) obj;
    return creationTime == that.creationTime
        && Objects.equals(topicName, that.topicName)
        && Objects.equals(config, that.config);
  }
@return true if the consumer group did not already subscribe this topic
iotdb-core/node-commons/src/main/java/org/apache/iotdb/commons/subscription/meta/topic/TopicMeta.java