pytorch

0dbd7293 - Split comm hooks into python-dependent hooks and others (#47019)

Split comm hooks into python-dependent hooks and others (#47019) Summary: Stack from [ghstack](https://github.com/ezyang/ghstack): * **https://github.com/pytorch/pytorch/issues/47019 Split comm hooks into python-dependent hooks and others** This is needed because we plan to move most of c10d C++ implementation into `libtorch_*.so`, which can not have Python dependencies. Pull Request resolved: https://github.com/pytorch/pytorch/pull/47019 Reviewed By: albanD Differential Revision: D24614129 Pulled By: gmagogsfm fbshipit-source-id: 3f32586b932a2fe6a7b01a3800f000e66e9786bb