External stream (#59527)
Summary:
Previous is https://github.com/pytorch/pytorch/issues/57781
We add now two CUDA bindings to avoid using ctypes to fix a windows issue.
However, we use ctypes to allocate the stream and create its pointer
(we can do this with a 0-dim tensor too if it feels better).
CC. ezyang rgommers ngimel mruberry
Pull Request resolved: https://github.com/pytorch/pytorch/pull/59527
Reviewed By: albanD
Differential Revision: D29053062
Pulled By: ezyang
fbshipit-source-id: 661e7e58de98b1bdb7a0871808cd41d91fe8f13f
