Naively I think you can probably just expose interactions with them inside existing apis like "slice::split_at_mut", since the rust abstract machine already has

Naively I think you can probably just expose interactions with them inside existing apis like "slice::split_at_mut", since the rust abstract machine already has the concept of pointers being able to access regions of memory. You would probably have direct access to the primitives available, but discourage using them, because using them means non portable code.