protected override void OnElementChanged(ElementChangedEventArgs<View> e)
        {
            base.OnElementChanged(e);

            if (e.OldElement != null)
            {

            }

            if (e.NewElement != null)
            {
                var formsMap = (Classes.CustomMap.CustomMap)e.NewElement;
                circle = formsMap.Circle;

                ((MapView)Control).GetMapAsync(this);
            }
        }
        public void OnMapReady(GoogleMap googleMap)
        {
            map = googleMap;

            if (circle == null)
            {
                circle = new CustomCircle
                {
                    Position = new Position {Longitude = 37.79752, Latitude = -122.40183 },
                    Radius =  3000D
                };
            }

            var circleOptions = new CircleOptions();
            circleOptions.InvokeCenter(new LatLng(circle.Position.Latitude, circle.Position.Longitude));
            circleOptions.InvokeRadius(circle.Radius);
            circleOptions.InvokeFillColor(0X66B0171F);
            circleOptions.InvokeStrokeColor(0X66FF0000);
            circleOptions.InvokeStrokeWidth(0);
            map.AddCircle(circleOptions);
        }