Fix checksum calculation bug when the payload is a CompositeByteBuf with readerIndex > 0 #1333

Job	Run time
PR Validation	7m 42s
Integration Tests	6m 57s
Backward compatibility tests	3m 41s
Build with macos on JDK 11	6m 10s
Bookie Tests	21m 6s
Build with windows on JDK 11	5m 44s
Compatibility Check Java8	19m 34s
Client Tests	1h 0m 14s
OWASP Dependency Check	0s
Compatibility Check Java11	20m 10s
Replication Tests	25m 44s
Compatibility Check Java17	19m 15s
Remaining Tests	18m 40s
TLS Tests	13m 13s
StreamStorage Tests	18m 41s
Shell tests	23s
	4h 7m 14s

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