RC_NOTIFY_DRAIN
assert(!(rnip->rni_flags & RC_NOTIFY_DRAIN));
rnip->rni_flags |= RC_NOTIFY_DRAIN;
rnip->rni_flags &= ~(RC_NOTIFY_DRAIN | RC_NOTIFY_ACTIVE);
while ((rnip->rni_flags & (RC_NOTIFY_ACTIVE | RC_NOTIFY_DRAIN)) ==
assert(!(rnip->rni_flags & (RC_NOTIFY_DRAIN | RC_NOTIFY_EMPTYING)));