_AddUnknownThread
thread = _AddUnknownThread(event->thread);
thread = _AddUnknownThread(event->thread);
thread = _AddUnknownThread(event->thread);
thread = _AddUnknownThread(event->thread);
thread = _AddUnknownThread(event->thread);
thread = _AddUnknownThread(event->previous_thread);
ExtendedThreadSchedulingState* _AddUnknownThread(