Class EchoWorker

test/async_worker.cc:202–219

};

class EchoWorker : public AsyncWorker {
 public:
  EchoWorker(Function& cb, std::string& echo) : AsyncWorker(cb), echo(echo) {}
  ~EchoWorker() {}

  void Execute() override {
    // Simulate cpu heavy task
    std::this_thread::sleep_for(std::chrono::milliseconds(30));
  }

  void OnOK() override {
    HandleScope scope(Env());
    Callback().Call({Env().Null(), String::New(Env(), echo)});
  }

 private:
  std::string echo;
};

class FailCancelWorker : public AsyncWorker {
 private: