040000 tree 996529f80be3b12faaa0b8c5c0f9084d80dbed1d	condition_variable
040000 tree d6115974e2edb8d61019e4d807cf3d377ea0f65a	future
040000 tree a6f73db03081e690a90aaf4269a554b6e68600cc	mutex
040000 tree e29ed20b69207caa96a033b3e92712f6d8f3c3cd	thread