The next free submission entry, zeroed, or null when the submission queue is full (submit, then
ask again). Fill it in (prep_rw, prep_nop or by hand), set user_data, and call submit. With
IORING_SETUP_SQE128 the entry is 128 bytes: cast it to io_uring_sqe128.
get_sqe :: (ring: *Ring) -> *io_uring_sqeParameters
- ring: *Ring