public BitmapImageRequest(TileImageDelegate getImage, object userToken, BitmapImageRequestCompletedHandler callback)
 {
     GetImage  = getImage;
     UserToken = userToken;
     Callback  = callback;
 }
 public BitmapImageRequest(Uri uri, object userToken, BitmapImageRequestCompletedHandler callback)
 {
     Uri       = uri;
     UserToken = userToken;
     Callback  = callback;
 }
        public BitmapImageRequest CreateRequest(TileImageDelegate getImage, NetworkPriority networkPriority, object userToken, BitmapImageRequestCompletedHandler callback)
        {
            var bitmapImageRequest = new BitmapImageRequest(getImage, userToken, callback)
            {
                NetworkPriority = networkPriority
            };

            lock (pendingRequests)
                pendingRequests.Add(bitmapImageRequest);
            thereMayBeWorkToDo.Set();
            return(bitmapImageRequest);
        }