doadd
doadd(ev, ev->option.io.fd = fd, VERTO_EV_TYPE_IO);
doadd(ev, ev->option.interval = interval, VERTO_EV_TYPE_TIMEOUT);
doadd(ev,, VERTO_EV_TYPE_IDLE);
doadd(ev, ev->option.signal = signal, VERTO_EV_TYPE_SIGNAL);
doadd(ev, ev->option.child.proc = proc, VERTO_EV_TYPE_CHILD);