Rclone Declare Sync Directories?

I'm seeing varying types of cache posts, but not quite what I'm looking for - so I guess it's going to be a feature request unless my google-fu is just broken.

So I have vfs cacheing enabled, and it caches in the ~/.cache/rclone/vfs (linux) for the duration of my max-age parameter.

What I'm essentially looking for (or requesting) is some sort of flag that will keep a directory persistently in that state. So for example:

--persistent-cache = "my-remote:/Documents"

I could keep it cached via vfs it will stay local kind of like those offline/online sync settings the proprietary clients use.

Rclone has been 100% necessary as my work uses Office 365 and I've been able to mount my onedrive/sharepoint directories but there are just several quirks that I feel like would be resolved by implementing this. For example, when opening a csv or xlsx, Libreoffice tries to import blank data and the temp-open state has caused files to become corrupt. I can go in the web and restore but I feel like if I could declare a directory to be cached, my everyday job would be much easier.

I can't find it quickly, but there already is an issue out there for a persistent cache type.

The cache backend has so many bugs, I'd not recommend to go near that.

I think @ncw had some thoughts for the next revision of the vfs cache that would be for that.