X-Amz-Content-Sha256 not handled

When I Post data to S3, I must to send X-Amz-Content-Sha256 header.
In AWSV4Auth.java there isn't this business logic.

I tried to change source code, but I receive the following error message:

<Error><Code>XAmzContentSHA256Mismatch</Code><Message>The Content-SHA256 you specified did not match what we received</Message><Resource>bucket_prova1/filedaStandalone9.txt</Resource><RequestId>0c07c835:16b79321460:646d:60a</RequestId></Error>