async onShutdownDevice(event) {
    Object.assign(this.context, {
      deviceId: '',
      bundleId: '',
      launchArgs: null,
      pid: NaN,
      isAppReady: undefined,
    });
  }
Hook that is supposed to be called from device.shutdown()

@protected
@async
@param {Object} event - Device shutdown event object
@param {string} event.deviceId - Current deviceId
@return {Promise<void>} - when done