Simplify OwnerRRef completion (#57853)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/57853
A bunch of methods received an OwnerRRef to "fill in". I think it will be more flexible to do it the other way around, and have these methods return a value (wrapped in a Future), which can then be "connected" to an OwnerRRef, but which can also potentially be consumed in different ways.
ghstack-source-id: 129567059
Test Plan: CI
Reviewed By: mrshenli
Differential Revision: D28253844
fbshipit-source-id: 7e3772312dbacfc75a6ac0f62189fc9828001fc7
