* s3api: copy the trailer checksum before reading the next trailer line
parseChunkChecksum kept the checksum value as a sub-slice of the line
returned by bufio.Reader.ReadSlice, which is only valid until the next
read. When the trailer lines arrive in separate TCP segments, reading
x-amz-trailer-signature refills the buffer and overwrites the saved
value, so a correct upload fails with InvalidDigest ("The Content-Md5
you specified is not valid").
The AWS SDK for Java v2 (>= 2.30) on a Linux JDK sends the trailer that
way; about half of its signed streaming uploads failed.
Fixes#11582
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
* s3api: reuse crc32 writer and trim comments in trailer split test
---------
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: Chris Lu <chris.lu@gmail.com>
