Release GIL before destructing RPCAgent subclasses. (#57029)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/57029
Partially addresses https://github.com/pytorch/pytorch/issues/56297
This fixes deadlocks when the threads the RPCAgent are blocking
on try to take the GIL. This also adds a general utility for
making shared_ptr run destructors without GIL.
Signed-off-by: Edward Z. Yang <ezyang@fb.com>
Test Plan: Imported from OSS
Reviewed By: albanD
Differential Revision: D28030294
Pulled By: ezyang
fbshipit-source-id: 628c066eebbb70bda5b914645a109dce35d73c8d
