public override void Add(Uri uri, TimeSpan lifeSpan, Stream stream)
        {
            bool result = BrowserCache.Add(uri.AbsoluteUri, stream, DateTime.Now.AddHours(1));

            Debug.Assert(result, "failed to add to cache");
        }
        public override bool TryGet(Uri uri, out Stream stream)
        {
            stream = BrowserCache.Get(uri.AbsoluteUri);

            return(stream != null);
        }