_sleepq_wait_begin
(void)_sleepq_wait_begin(td, sc, wc, 0, PINTERLOCKED);
ret = _sleepq_wait_begin(td, sc, wc, 0, PINTERLOCKED | PCATCH);
ret = _sleepq_wait_begin(td, sc, wc, td->td_sqtimo, PINTERLOCKED);
ret = _sleepq_wait_begin(td, sc, wc, td->td_sqtimo,