Method dequeue

src/common/QueueRing.h:34–42

    }

    void dequeue(T *entry) {
      std::unique_lock l(lock);
      while (entries.empty()) {
        cond.wait(l);
      };
      ceph_assert(!entries.empty());
      *entry = entries.front();
      entries.pop_front();
    };
  };

  std::vector<QueueBucket> buckets;