040000 tree 32dda37b9e3e8f7e8be2db4970515c15d1aa77dc	condition_variable
040000 tree 0b121869082010a98a0efda505c5e3623551edc8	future
040000 tree 2dcf5e25abdaf3979511736f3a1e95a379e82ae3	mutex
040000 tree c31db8255f57b7fea2ff21659484a81e00b416a7	thread