public int getMaxMsgSize(String topicName) {
        return msgSizeHolder.getDefMaxMsgSize(topicName);
    }
Get allowed message size.

@param topicName  the topic name
@return max allowed message size
inlong-tubemq/tubemq-client/src/main/java/org/apache/inlong/tubemq/client/producer/ProducerManager.java