boost.asio as well seems [1] to have io_uring support, including registered buffers. It was experimental in 1.21; lots of fixes since, don't know if it is currently considered stable.

Asio supports async/await, stackful coroutines and plain old manual continuation passing.

[1] https://think-async.com/Asio/asio-1.36.0/doc/asio/history.ht...