Method wait_for_fd

io/kqueue.cpp:102–121

    }

    int wait_for_fd(int fd, uint32_t interests, Timeout timeout) override {
        if (unlikely(interests == 0)) {
            errno = ENOSYS;
            return -1;
        }
        auto current = CURRENT;
        short ev = (interests == EVENT_READ) ? EVFILT_READ : EVFILT_WRITE;
        int ret = enqueue(fd, ev, EV_ADD | EV_ONESHOT, 0, current);
        if (ret < 0) return ret;
        SCOPED_PAUSE_WORK_STEALING;
        ret = thread_usleep(timeout);
        ERRNO err;
        if (likely(ret == -1 && err.no == EOK)) {
            return 0;  // event arrived
        }

        enqueue(fd, ev, EV_DELETE, 0, current, true);
        errno = (ret == 0) ? ETIMEDOUT : err.no;
        return -1;
    }

    ssize_t wait_and_fire_events(uint64_t timeout) override {
        ssize_t nev = 0;