Add `WeakLoopHandle` #629

Job	Run time
lint	31s
CI (Windows) (1.63.0)	2m 42s
CI (1.63.0)	1m 30s
CI (Windows) (stable)	2m 44s
CI (1.69.0)	1m 47s
CI (stable)	1m 9s
CI (beta)	1m 6s
Coverage	0s
Documentation on Github Pages	0s
	11m 29s

Provide feedback