How to detect the first drag after map is loaded

MapDidDrag.swift

class MapViewController: UIViewController {
    var isLoaded = false
}

extension MapViewController: MKMapViewDelegate {
    func mapViewDidChangeVisibleRegion(_ mapView: MKMapView) {
        if isLoaded { 
            mapDidDrag()
        }
     }
    
    func mapViewDidFinishLoadingMap(_ mapView: MKMapView) {     
        isLoaded = true
    }
}