Method Unlock

cpp/src/arrow/util/async_util_test.cc:385–385

  }
  virtual void Release(int amt) {}
  void Unlock() { gate_.MarkFinished(); }
  int Capacity() { return std::numeric_limits<int>::max(); }
  virtual void Pause() { FAIL() << "Should not get here."; }
  virtual void Resume() { FAIL() << "Should not get here."; }