ZSD_SHUTDOWN_NEEDED
if (t->zsd_flags & ZSD_SHUTDOWN_NEEDED) {
t->zsd_flags &= ~ZSD_SHUTDOWN_NEEDED;
del->zsd_flags |= ZSD_SHUTDOWN_NEEDED;
t->zsd_flags |= ZSD_SHUTDOWN_NEEDED;
(ZSD_SHUTDOWN_NEEDED|ZSD_SHUTDOWN_INPROGRESS|ZSD_SHUTDOWN_COMPLETED)