Race condition with S3 PutObject upload stream with Netty client

[vigoo]

It fails with Data read has a different checksum than expected, but it can randomly pass if pausing it with a debugger for example.

My investigation shows that the stream gets drained and bytes sent to the Netty channel, still in the checksum validator the response metadata (from localstack) contains a different checksum and the content length is reported as 0.

There is a test case in the integtests subproject to reproduce it.

[vigoo]

NOTE: if content length is known and it's set on the request object, it works correctly.