https://lib.rs/crates/glommio depends on https://lib.rs/crates/lockfree which is unmaintained and also unsound (using std::mem::uninitialized). I have tried reaching out to the author of the crate on their gitlab and plan to file an rustsec advisory when the 90 days are up (14th November).
As your reverse dependency is one of the more downloaded ones I thought I would give you a heads up so that you can switch to something else before then.