_t_adjust_state
if ((rstate = _t_adjust_state(fd, T_IDLE)) < 0) {
if ((rstate = _t_adjust_state(fd, T_DATAXFER)) < 0) {
if ((rstate = _t_adjust_state(fd, T_INREL)) < 0) {
static int _t_adjust_state(int fd, int instate);