i_so_notify_last_tx
(void) i_so_notify_last_tx(so, &pollev, &sigev);
(void) i_so_notify_last_tx(so, &pollev, &sigev);
(void) i_so_notify_last_tx(so, &pollev, &sigev);
static int i_so_notify_last_tx(struct sonode *, int *, int *);