Find other places we can use async RwLock

[benthecarman]

          There's probably other places in the codebase we can do this too, would be a good followup

Originally posted by @benthecarman in #924 (comment)

[AnthonyRonning]

Well, clippy warns when you're using a non async mutex over an await so we aren't doing it currently but maybe we benefit from doing that swap anyways.