class RecordMetadata {

    @Deprecated
    public long checksum() {
        if (checksum == null)
            // The checksum is null only for message format v2 and above, which do not have a record-level checksum.
            this.checksum = DefaultRecord.computePartialChecksum(timestamp, serializedKeySize, serializedValueSize);
        return this.checksum;
    }

    public  RecordMetadata(TopicPartition topicPartition, long baseOffset, long relativeOffset, long timestamp,
                          Long checksum, int serializedKeySize, int serializedValueSize);

}