Setting up a custom callout on the detailCalloutAccessoryView in a MapView

CustomCallout.swift

    func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {
        if annotation is MKUserLocation {
            return nil
        }
        var annotationView = mapView.dequeueReusableAnnotationView(withIdentifier: "PlaceAnnotationView") as? MKMarkerAnnotationView
        if annotationView == nil { 
            annotationView = MKMarkerAnnotationView(annotation: annotation, reuseIdentifier: "PlaceAnnotationView")
            annotationView?.canShowCallout = true
        } else {
            annotationView?.annotation = annotation
        }
        
        // initialize your custom view 
        let customCalloutView = CustomCalloutView()
        customCalloutView.delegate = self 
        
        // setup constraints for custom view 
        customCalloutView.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            customCalloutView.widthAnchor.constraint(equalToConstant: UIScreen.main.bounds.width * 0.60),
            customCalloutView.heightAnchor.constraint(equalToConstant: UIScreen.main.bounds.height * 0.30)
        ])
        
        // set detailCalloutAccessoryView
        annotationView?.detailCalloutAccessoryView = customCalloutView

        return annotationView
        
    }