SuggestusinganatomicvalueinsteadofaMutexwherepossible

Fixes #352
First try, so this might not be ready to merge yet. I'd appreciate any feedback.
One thing I'm wondering is whether it would make sense to warn for uses of e.g.

. I currently only warn for

and

and ignore all the other integer types, but I could imagine scenarios where someone uses a

but would be willing to switch to an

.

该提问来源于开源项目：rust-lang/rust-clippy