google地图中两个标记之间的路径- Swift

import UIKit
import GoogleMaps

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        
        let mapView = GMSMapView(frame: CGRect.zero)
        self.view = mapView
        
        let marker1 = GMSMarker()
        marker1.position = CLLocationCoordinate2D(latitude: 37.7749, longitude: -122.4194)
        marker1.title = "San Francisco"
        marker1.map = mapView
        
        let marker2 = GMSMarker()
        marker2.position = CLLocationCoordinate2D(latitude: 34.0522, longitude: -118.2437)
        marker2.title = "Los Angeles"
        marker2.map = mapView
        
        let path = GMSMutablePath()
        path.add(CLLocationCoordinate2D(latitude: 37.7749, longitude: -122.4194))
        path.add(CLLocationCoordinate2D(latitude: 34.0522, longitude: -118.2437))
        
        let polyline = GMSPolyline(path: path)
        polyline.strokeWidth = 3.0
        polyline.map = mapView
    }
}