fs_w
ev_io_init (&fs_w, infy_cb, fs_fd, EV_READ);
ev_set_priority (&fs_w, EV_MAXPRI);
ev_io_start (EV_A_ &fs_w);
ev_io_stop (EV_A_ &fs_w);
ev_io_set (&fs_w, fs_fd, EV_READ);
ev_io_start (EV_A_ &fs_w);
VARx(ev_io, fs_w)
#define fs_w ((loop)->fs_w)