Crate returns &'static str returned from transmuting a &str, which may become unsound at any time. It also has much more code than simply storing an std::io::Error in an Arc.

Simple futures-based wrapper on top of other crates, primarily polling.

simple macro

Code is trivial, but I feel like assuming 64-byte cache lines on non-ARM64/x64 might be overly optimistic.

only minor changes

Crate is simple enough, but I don't fully understand the low-level concurrency details.

proc-macro-hack wrapper crate

Very simple and minimal crate

Contains large amounts of UB and segfault-prone code. See https://github.com/servo/core-foundation-rs/issues/361 and https://github.com/servo/core-foundation-rs/issues/291.

adds some new features, no changes to existing code

changes imports for no_std, no changes to code

Most of what this crate does is simple, and it's very thoroughly commented.

Crate just consists of a few traits, which are all defined as you'd expect.

just refactoring

only minor changes

This crate is copy/pasted from core::mem::MaybeUninit for older rustc.

Simple crate. Triggers UB but there is no workaround on current Rust.

Mostly consists of types with a few simple helpers. Last commit is a year ago, but there aren't any outstanding issues or PRs and the author still seems to be active.

I reviewed this crate with default features. All code outside the sync module is simple and clearly correct, and the code in the sync module comes from std with minor changes.

Code is short and seems reasonable, but I'm not great at low-level concurrent code.

Simpler version of pin-project

Very small crate, has useful macros

I primarily reviewed the code for Linux, and quickly skimmed other OSes to make sure they weren't doing anything obviously malicious. The Linux code seems to map cleanly to epoll, though there may be subtleties in the underlying API I'm unaware of.

changes seem clear