b2795b799e
Summary: This is not a generic thread local implementation in the sense that it only takes pointer. But it does support multiple instances per thread and lets user plugin function to perform cleanup when thread exits or an instance gets destroyed. Test Plan: unit test for now Reviewers: haobo, igor, sdong, dhruba Reviewed By: igor CC: leveldb, kailiu Differential Revision: https://reviews.facebook.net/D16131