feat(core)!: implement write returns metadata for s3

[meteorgan]

Which issue does this PR close?

Part of #5557

Rationale for this change

What changes are included in this PR?

• implement write returns metadata for Operator and BlockingOperator
• implement the logic for service S3
• other services return default Metadata after writing
• skip return value for language bindings

Are there any user-facing changes?

Yes.

• write, write_with in Operator returns Result<Metadata> instead of Return<()>
• Writer.close() returns Return<Metadata> instead of Return<()>
• write in BlockingOperator returns Return<Metadata> instead of Return<()>
• FunctionWrite.call() used by BlockingOperator returns Return<Metadata> instead of Return<()>

[meteorgan]

emmm, another issue related to ceph rados: the Etag returned by CompleteMultipartUpload doesn't follow the standard.

[Xuanwo]

the Etag returned by CompleteMultipartUpload doesn't follow the standard.

Well, well, well...

Let's do our best to permit this since it's not harmful. Technically, we don't allow users to parse the ETag value; instead, they should store it and compare it with values from the same source. I'm guessing the issue lies in part of our code assuming that the ETag must contain "?

[meteorgan]

the Etag returned by CompleteMultipartUpload doesn't follow the standard.

Well, well, well...

Let's do our best to permit this since it's not harmful. Technically, we don't allow users to parse the ETag value; instead, they should store it and compare it with values from the same source. I'm guessing the issue lies in part of our code assuming that the ETag must contain "?

No. The issue is that I compare the Etag from stat with the one from write in the tests to ensure we get the correct Etag if it's returned by write. However, the value returned from stat contain " while the value returned from write does not. they aren't consistent with each other, even within the same service !

[Xuanwo]

No. The issue is that I compare the Etag from stat with the one from write in the tests to ensure we get the correct Etag if it's returned by write. However, the value returned from stat contain " while the value returned from write does not. they aren't consistent with each other, even within the same service !

That's really surprising. Let's disable the Ceph RADOS test and create an issue to track it. I believe such a bug isn't worth our workaround.