peek_cqe

The oldest unconsumed completion in cqe, without waiting: returns 0, or -EAGAIN when there is none. The pointer stays valid until cqe_seen. A ring that only produces completions when it enters the kernel (DEFER_TASKRUN, IOPOLL, or one with overflowed completions) is entered once to collect them.

peek_cqe :: (ring: *Ring, cqe: **io_uring_cqe) -> s32