Extension to fit annotaion with a given location

MKMapView+FitAnnotaion.swift

extension MKMapView {
    func fitMapViewToAnnotaion(withEdgePadding edgePadding:UIEdgeInsets = UIEdgeInsets(top: 20, left: 20, bottom: 20, right: 20), andLocation givenLocation:CLLocationCoordinate2D?) -> Void {
        var zoomRect:MKMapRect = MKMapRect.null
        
        for annotation in annotations {
            let aPoint:MKMapPoint = MKMapPoint(annotation.coordinate)
            let rect:MKMapRect = MKMapRect(x: aPoint.x, y: aPoint.y, width: 0.1, height: 0.1)
            
            if zoomRect.isNull {
                zoomRect = rect
            } else {
                zoomRect = zoomRect.union(rect)
            }
        }
        
        if let location = givenLocation {
            let aPoint:MKMapPoint = MKMapPoint(location)
            let rect:MKMapRect = MKMapRect(x: aPoint.x, y: aPoint.y, width: 0.1, height: 0.1)
            
            if zoomRect.isNull {
                zoomRect = rect
            } else {
                zoomRect = zoomRect.union(rect)
            }
        }
        
        setVisibleMapRect(zoomRect, edgePadding: edgePadding, animated: true)
    }
}