location.swift

    func startUpdatingLocation() {
        self.locationManager.desiredAccuracy = kCLLocationAccuracyBest
        self.locationManager.activityType = .fitness
        self.locationManager.startUpdatingLocation()
    }

extension ViewController: CLLocationManagerDelegate {
    func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
        if status == .authorizedWhenInUse {
            self.startUpdatingLocation()
        }
    }
    
    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        guard let location = locations.last else {
            return
        }
        DispatchQueue.main.async {
             self.accuracyLabel.text = "\(location.horizontalAccuracy)"
        }
    }
}