Method release_worker

src/msg/async/Stack.h:328–331

  PerfCounters *get_perf_counter() { return perf_logger; }
  PerfCounters *get_labeled_perf_counter() { return perf_labeled_logger; }
  void release_worker() {
    int oldref = references.fetch_sub(1);
    ceph_assert(oldref > 0);
  }
  void init_done() {
    init_lock.lock();
    init = true;