Removing usage of private/unstable Ray APIs

[edoakes]

Hi all, I am one of the maintainers of Ray. I was auditing the Ray codebase and trying to clean up some private/unstable APIs and I came across two usages in the RayDP codebase:

1) Passing an owner to Ray.put

This is an API that was introduced as experimental and never stabilized. We are not comfortable maintaining it going forward as it further complicates the already-complex reference counting protocol. What is the path to removing this? I can help devise an alternative if you can provide more context about what it is used for.

2) ray.worker.global_worker

This is a private attribute of Ray that has since been moved to ray._private and now logs a deprecation warning on access. If you can document the specific metadata that you need from it, we can consider adding stable APIs to access that information.