pytorch

0a975d33 - add pre-packing operation in README.md (#17151)

add pre-packing operation in README.md (#17151) Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/17151 As title Reviewed By: jianyuh Differential Revision: D14084272 fbshipit-source-id: e58c041e0374f6e82b337e5b6325ef06981ad8b4