question: private static byte [ ] readCheckedBytes ( byte [ ] buffer , int dataSize ) throws InvalidProtocolBufferNanoException { BackupProtos . CheckedMessage wrapper = new BackupProtos . CheckedMessage ( ) ; MessageNano . mergeFrom ( wrapper , buffer , 0 , dataSize ) ; CRC32 checksum = new CRC32 ( ) ; checksum . update ( wrapper . payload ) ; if ( wrapper . checksum != checksum . getValue ( ) ) { throw new InvalidProtocolBufferNanoException ( "checksum does not match" ) ; } return wrapper . payload ; }
target:  Unwrap a proto message from a CheckedMessage, verifying the checksum. 