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