GAT/PointerFamily existing crate

I have been reading up on the GAT proposal and I know that it is near to stability.

In the RFC, there is a nice example of how to abstract over Rc`Arc`.

https://rust-lang.github.io/rfcs/1598-generic_associated_types.html

I doing something similar in my own library at the moment (but much less general) and it's fairly painful. So I am wondering two things:

When GAT stabilizes will it offer anything like this in std, or will actually uses of GAT come later. And are there any crates available that offer this kind of abstraction of Rc`Arc` even if they require nightly at the moment?

The reason I ask, is that if I am going to get a more general way of achieving this in the near future, this might be the way to go as compared to my own current approach even if it pushes me onto nightly for a short while.