@Override
    public boolean isClosedTopic(final String topic) {
        return this.closedTopicMap.get(topic) != null;
    }
Broker's metadata management util. Metadata contains broker's default configurations, topics,
topic that will be deleted, and broker's policy definition.
Metadata is got from Master service, it will refresh in heartbeat between broker and master.
inlong-tubemq/tubemq-server/src/main/java/org/apache/inlong/tubemq/server/broker/metadata/BrokerMetadataManager.java