Improve IOBuf::clone and IOBuf::cloneOne() perf
Improve IOBuf::clone and IOBuf::cloneOne() perf

Summary: Improve IOBuf::clone and IOBuf::cloneOne() perf

Reviewed By: yfeldblum

Differential Revision: D20882203

fbshipit-source-id: ce37c2bf3c0fbdbe3c316856dc431a0108e4b9bf

facebook/folly,facebook/folly,facebook/folly,facebook/folly,facebook/folly