Method enqueue

kernel/orbis/src/umtx.cpp:83–92

static auto umtxStorage = createGlobalObject<UmtxStorage>();

std::pair<const UmtxKey, UmtxCond> *UmtxChain::enqueue(UmtxKey &key,
                                                       Thread *thr) {
  if (!spare_queue.empty()) {
    auto node = spare_queue.extract(spare_queue.begin());
    node.key() = key;
    node.mapped().thr = thr;
    return &*sleep_queue.insert(std::move(node));
  }
  return &*sleep_queue.emplace(key, thr);
}

void UmtxChain::erase(std::pair<const UmtxKey, UmtxCond> *obj) {
  for (auto [it, e] = sleep_queue.equal_range(obj->first); it != e; it++) {