public static void Reverse(Esri.ArcGISRuntime.Geometry.PointCollection pts)
        {
            IEnumerable<MapPoint> reversedPts = pts.Reverse();

            Esri.ArcGISRuntime.Geometry.PointCollection newPts =
                new Esri.ArcGISRuntime.Geometry.PointCollection();
            foreach (MapPoint pt in reversedPts)
                newPts.Add(pt);

            pts.Clear();
            foreach (MapPoint pt in newPts)
                pts.Add(pt);
        }