Cloud file provider APIs on Windows and MacOS

Both Windows and MacOS now offer APIs specifically for synchronizing files between local disks (NTFS and APFS only, respectively) and cloud storage.
This is Microsoft's API: Cloud Sync Engines - Win32 apps | Microsoft Docs
This is Apple's API: Apple Developer Documentation

Also, Apple announced the deprecation of kernel extensions: Deprecated Kernel Extensions and System Extension Alternatives - Support - Apple Developer
This puts the future of macFUSE in question. They specifically say that kernel APIs will be deprecated slowly as userland alternatives are provided. We have a userland API for file providers. Whatever macFUSE uses is clearly queued for the guillotine.

These APIs also provide nice-to-have features that FUSE doesn't have (on any platform): the ability to tell the user (via Windows Explorer and Finder) which files are hydrated, which aren't, as well as download/upload progress, and also the ability to pin files so they are always available offline.

I realize that implementing these will require quite a bit of effort. The Windows Cloud Files API is C/C++, which shouldn't require any rocket surgery to implement in Go (right....?). The MacOS API is only available in Swift and Objective-C. I expect this to be trickier but not impossible.

Sadly I don't know any Go (or Swift, or Objective-C) so I can't even begin to size the effort here.

Good links thanks!

That looks like it could be implemented by an objective C app which uses rclone as a library.

Possibly, though I'm not sure that the sync api above obsoletes a full filesystem.

Linking Go with C is a bit of a pain. Win32 APIs are relatively easy to use from Go - but no idea about Objective-C.

I suspect the macOS solution would be to write an objective-c or swift app which uses rclone as a library. That might work for the Windows platform too. That is certainly how I'd prototype it anyway.

Developing file sync servers that use rclone as a library sounds like a sensible idea to me.
Does rclone even compile as a library, that exports C-compatible symbols, or something like that?