[FLINK-39331] Add @Experimental annotation to public Native S3 classes

[Samrat002]

What is the purpose of the change

Mark the public API classes in flink-s3-fs-native as experimental to signal to users that this feature is still evolving and may undergo changes in future releases.

Brief change log

Mark following public class with @Experimental

1. NativeS3FileSystemFactory
2. NativeS3AFileSystemFactory
3. NativeS3OutputStream
4. NativeS3RecoverableFsDataOutputStream
5. NativeS3Committer

Verifying this change

Existing UT suffices.

Does this pull request potentially affect one of the following parts:

• Dependencies: no
• The public API, i.e., is any changed class annotated with @Public(Evolving): yes (marked as @Experimental)
• The serializers: no
• The runtime per-record code paths (performance sensitive): no
• Anything that affects deployment or recovery: no
• The S3 file system connector: yes

Documentation

• Does this pull request introduce a new feature? no
• If yes, how is the feature documented? not applicable

[flinkbot]

CI report:

• b3df798 Azure: SUCCESS
• 1f8d3e7 Azure: PENDING

Bot commands

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• @flinkbot run azure re-run the last Azure build

[Izeren]

Thank you for the PR @Samrat002, I wonder if we should rather reduce visibility of the classes than adding experimental annotation to them (except for factories)

[Izeren]

@Samrat002, In addition, should we downgrade: NativeS3FileSystem, NativeS3InputStream, NativeS3Recoverable, NativeS3RecoverableSerializer to package-private or Internal@?

Also, NativeS3RecoverableWriter is marked as @PublicEvolving, and it should be Experimental@ as well

[Samrat002]

@Samrat002, In addition, should we downgrade: NativeS3FileSystem, NativeS3InputStream, NativeS3Recoverable, NativeS3RecoverableSerializer to package-private or Internal@?

Yes . right thing to do and reduce the API visiblity . i have made the classes NativeS3FileSystem, NativeS3InputStream, NativeS3Recoverable, NativeS3RecoverableSerializer to package-private

Also, NativeS3RecoverableWriter is marked as @PublicEvolving, and it should be Experimental@ as well

yes. my miss. fixed it now