* filer: match If-Match and If-None-Match against "*" and ETag lists
checkPreconditions compared the whole header as one ETag, so "*", a
list of ETags and a weak W/ tag in If-None-Match never matched
(RFC 9110 13.1.1, 13.1.2).
* filer: split etag lists only outside quoted tags
A comma inside a quoted opaque tag is a legal etagc, not a list
separator; strings.Split cut such tags into fragments that
CanonicalizeETag could turn into a false match.
Generated with [Devin](https://devin.ai)
Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* filer: match repeated If-Match and If-None-Match header lines
Header.Get reads only the first field line, so a match on a later
repeated header was missed; join all field values like any other
comma-separated list.
Generated with [Devin](https://devin.ai)
Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* filer: ignore empty elements in etag precondition lists
* filer: let a present-but-empty precondition line suppress the date check
---------
Co-authored-by: user.email <chrislusf@users.noreply.github.com>
Co-authored-by: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Co-authored-by: chrislusf <chris.lu@gmail.com>
