Ios Swift-用户单击按钮时如何显示Mapkit注释

我是Xcode Swift故事板的新手，我试图在用户单击按钮时在mapkit中显示地图注释。现在，使用当前代码，注释（pin）从开始显示，我想嵌入到按钮中，以便在用户按下按钮后在地图中显示。以下是与注释相关的代码段：

  let pin = MKPointAnnotation()
    pin.coordinate = coordinate
    mapView.addAnnotation(pin)
}

以下是完整的代码：

import CoreLocation
import MapKit
import UIKit

class ViewController: UIViewController, CLLocationManagerDelegate {
    
    @IBOutlet var mapView: MKMapView!
    
    let manager = CLLocationManager()

    override func viewDidLoad() {
        super.viewDidLoad()
        
    }

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        manager.desiredAccuracy  = kCLLocationAccuracyBest
        manager.delegate = self
        manager.requestWhenInUseAuthorization()
        manager.startUpdatingLocation()
    }
    
    func locationManager( _ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]){
        if let location = locations.first{
            manager.stopUpdatingLocation()
            
            render(location: location)
        }
    }
    
    func render(location: CLLocation){
        
        let coordinate = CLLocationCoordinate2D(latitude: location.coordinate.latitude, longitude: location.coordinate.longitude)
        
        let span = MKCoordinateSpan(latitudeDelta: 0.1, longitudeDelta: 0.1)
        
        let region = MKCoordinateRegion(center: coordinate, span: span)
        
        mapView.setRegion(region, animated: true)
        
        let pin = MKPointAnnotation()
        pin.coordinate = coordinate
        mapView.addAnnotation(pin)
    }
}