如何使用自定义地图渲染ios在大头针从a点拖动到b点时获取坐标

import MapKit

@IBOutlet weak var mapView: MKMapView!

let initialLocation = CLLocation(latitude: 37.7749, longitude: -122.4194)
let regionRadius: CLLocationDistance = 1000

func centerMapOnLocation(location: CLLocation) {
    let coordinateRegion = MKCoordinateRegion(center: location.coordinate, latitudinalMeters: regionRadius, longitudinalMeters: regionRadius)
    mapView.setRegion(coordinateRegion, animated: true)
}

override func viewDidLoad() {
    super.viewDidLoad()
    centerMapOnLocation(location: initialLocation)
}

class CustomAnnotation: NSObject, MKAnnotation {
    var coordinate: CLLocationCoordinate2D

    init(coordinate: CLLocationCoordinate2D) {
        self.coordinate = coordinate
        super.init()
    }
}

func addAnnotation() {
    let annotation = CustomAnnotation(coordinate: initialLocation.coordinate)
    mapView.addAnnotation(annotation)
}

override func viewDidLoad() {
    super.viewDidLoad()
    centerMapOnLocation(location: initialLocation)
    addAnnotation()
}

func mapView(_ mapView: MKMapView, annotationView view: MKAnnotationView, didChange newState: MKAnnotationView.DragState, fromOldState oldState: MKAnnotationView.DragState) {
    if newState == .ending {
        let droppedAt = view.annotation?.coordinate
        // 在这里获取拖动后的坐标
        print("拖动后的坐标：\(droppedAt?.latitude), \(droppedAt?.longitude)")
    }
}

override func viewDidLoad() {
    super.viewDidLoad()
    mapView.delegate = self
    centerMapOnLocation(location: initialLocation)
    addAnnotation()
}