code: func (c *BackgroundService) StopObserving(service string) (*gcdmessage.ChromeResponse, error) {
  	var v BackgroundServiceStopObservingParams
  	v.Service = service
  	return c.StopObservingWithParams(&v)
  }
docs: // StopObserving - Disables event updates for the service.
  // service -  enum values: backgroundFetch, backgroundSync