Method AsyncBareProgressWorker

nan.h:2171–2176

class AsyncBareProgressWorker : public AsyncBareProgressWorkerBase {
 public:
  explicit AsyncBareProgressWorker(
      Callback *callback_,
      const char* resource_name = "nan:AsyncBareProgressWorker")
      : AsyncBareProgressWorkerBase(callback_, resource_name) {
    uv_mutex_init(&async_lock);
  }

  virtual ~AsyncBareProgressWorker() {
    uv_mutex_destroy(&async_lock);