如何使用iOS SDK删除谷歌地图路由折线？

import GoogleMaps

class MapViewController: UIViewController {
    var mapView: GMSMapView!
    var routePolyline: GMSPolyline?

    override func viewDidLoad() {
        super.viewDidLoad()

        // 创建地图视图
        let camera = GMSCameraPosition.camera(withLatitude: 37.7749, longitude: -122.4194, zoom: 12.0)
        mapView = GMSMapView.map(withFrame: view.bounds, camera: camera)
        view.addSubview(mapView)

        // 添加路由折线
        let path = GMSMutablePath()
        path.addLatitude(37.7749, longitude: -122.4194)
        path.addLatitude(37.3352, longitude: -122.0322)
        routePolyline = GMSPolyline(path: path)
        routePolyline?.strokeWidth = 3.0
        routePolyline?.map = mapView

        // 删除路由折线
        DispatchQueue.main.asyncAfter(deadline: .now() + 5.0) {
            self.routePolyline?.map = nil
        }
    }
}