wait_cqe_timeout

wait_cqe with a limit: returns -ETIME when no completion arrived within nanoseconds. Needs IORING_FEAT_EXT_ARG (Linux 5.11); returns -EOPNOTSUPP without it.

wait_cqe_timeout :: (ring: *Ring, cqe: **io_uring_cqe, nanoseconds: s64) -> s32