Object cohorts have been part of the Folly open-source library (under the name `hazptr_obj_cohort`) and in heavy use in production since 2018. (See CppCon 2021 *[Hazard Pointer Synchronous reclamation beyond](https://www.youtube.com/watch?v=lsy8RRq2hHM)* *[Concurrency TS2](https://www.youtube.com/watch?v=lsy8RRq2hHM)* for details about the evolution of support for synchronous reclamation in Folly).