OnceMutex

OnceMutex is used at run time in 38 crates (of which 10 optionally). It is a direct run-time dependency in 3 crates. It's used only as a dev dependency in 2 crates.

Depender (with downloads and own rev deps)			OnceMutex version
117K	2	regex-cache		^0.1
	2	kompact		^0.1
	1	lazy		*