protected override IObservable<ImageInfo> WhenLoadedInternal(Uri uri, Size size)
        {
            return Observable.Create<ImageInfo>(observer =>
                {
                    if (imageData != null)
                    {
                        var imageInfo = new ImageInfo(uri, size, imageData) { ForceFallback = true };
                        observer.OnNext(imageInfo);
                    }

                    observer.OnCompleted();

                    return () => { };
                });
        }
            private async void ProceedReqeustAsync(ImageLoadContext request)
            {
                try
                {
                    var imageResponse = await WebRequest.Create(request.Uri).GetResponseAsync();
                    var imageData = await imageResponse.GetResponseStream().ToArrayAsync();
                    var resizedImageInfo = await imageData.ResizeAsync(request.Size, true);

                    var result = new ImageInfo
                        {
                            Data = resizedImageInfo.Data,
                            Size = resizedImageInfo.Size,
                            Uri = request.Uri
                        };

                    request.Observer.OnNext(result);
                    request.Observer.OnCompleted();
                }
                catch (WebException ex)
                {
                    request.Observer.OnError(new ImageLoaderException(string.Format("An error occurred when loading the image on '{0}'", request.Uri), ex));
                }
                catch (Exception ex)
                {
                    request.Observer.OnError(new ImageLoaderException(string.Format("An error occurred when parsing loaded image on '{0}'", request.Uri), ex));
                }
                finally
                {
                    lock (this.pendingRequests)
                    {
                        if (this.pendingRequests.Any())
                        {
                            var newRequest = this.pendingRequests.First();
                            this.pendingRequests.RemoveFirst();

                            this.ProceedReqeustAsync(newRequest);
                        }
                        else
                        {
                            this.requestsCounter--;
                        }
                    }
                }
            }
 protected bool Equals(ImageInfo other)
 {
     return Size.Equals(other.Size) && Equals(Uri, other.Uri);
 }
 /// <summary>
 ///     Notifies that the image is loaded from fallback <see cref="BaseImageLoader"/>.
 /// </summary>
 /// <param name="image">
 ///     The loaded image.
 /// </param>
 /// <remarks>
 ///     Use this method to save/cache the loaded image. 
 /// </remarks>
 protected virtual void OnFallbackImageLoaded(ImageInfo image)
 {
 }