CALLOUT_FIRED
c->c_flags &= ~(CALLOUT_FIRED | CALLOUT_INVOKING);
expired = ((c->c_flags & CALLOUT_FIRED) != 0);
c->c_flags &= ~(CALLOUT_PENDING|CALLOUT_FIRED);
c->c_flags &= ~(CALLOUT_PENDING|CALLOUT_FIRED);
c->c_flags &= ~(CALLOUT_PENDING|CALLOUT_FIRED);
rv = ((c->c_flags & CALLOUT_FIRED) != 0);
rv = ((c->c_flags & (CALLOUT_PENDING|CALLOUT_FIRED)) != 0);
KASSERT((c->c_flags & CALLOUT_FIRED) == 0);
(CALLOUT_FIRED | CALLOUT_INVOKING);