Comment by Tuna-Fish
1 day ago
This works perfectly well, and allows using the type system to handle safety. But it also really limits how you handle memory, and makes it impossible to do things like filling out parts of existing objects, so a lot of people are reluctant to take the plunge.
That’s annoying for people writing bespoke low-level networking code, but for a high-level HTTP library it’s a rounding error in the overall complexity on display. I think the bigger barrier for Tokio is that the interplay between having an epoll instance and a io_uring instance on the same pool is problematic and can erase performance gains. If done greenfield you could implement the “normal” APIs with ‘IORING_OP_POLL_ADD’, but not all of the exposed ‘mio’ surface area can work this way - only the oneshot API.