question: public static Long truncateOpCRC32 ( String stream , DLSN dlsn ) { CRC32 crc = requestCRC . get ( ) ; try { crc . update ( stream . getBytes ( UTF_8 ) ) ; crc . update ( dlsn . serializeBytes ( ) ) ; return crc . getValue ( ) ; } finally { crc . reset ( ) ; } }
target:  Generate crc32 for TruncateOp.