Get Imgur image urls and display on CollectionView

        // Makes a request to Imgur API
        public void MakeRequest(){
            var request = (HttpWebRequest)WebRequest.Create("https://api.imgur.com/3/gallery/hot/viral/0.json");
            request.Headers.Add ("Authorization", "Client-ID " + "920c7e989ed4deb");
            request.Method = "GET";

            Task<WebResponse> task = Task.Factory.FromAsync (
                                         request.BeginGetResponse,
                                         asyncResult => request.EndGetResponse (asyncResult),
                                         (object)null);
            task.ContinueWith (t => ReadStreamFromResponse (t.Result));

        }
        // Read the stream response, parse it to JSON, get the image urls ignoring the albums
        private void ReadStreamFromResponse(WebResponse response){
            using (Stream responseStream = response.GetResponseStream ()) {
                using (StreamReader sr = new StreamReader (responseStream)) {
                    string content = sr.ReadToEnd ();
                    var json = JsonObject.Parse (content);
                    var array = json ["data"];

                    List<string> urls = new List<string> ();
                    foreach (JsonObject o in array) {
                        string url = o ["link"];
                        bool isAlbum = o ["is_album"];
                        if (!isAlbum) {
                            url = url.Insert (url.Length - 4, "s");
                            urls.Add (url);
                        }
                    }
                    totalPhotos = urls.Count;

                    foreach (var url in urls) {
                        AddElement (url);
                    }
                }
            }
        }
        // For each image url, get the data, place it in a UIImage and add it to collectionData,
        // then assign it to the CollectionSource's photos List object and call ReloadData
        public void AddElement(string url){


            using (var imgUrl = new NSUrl (url)) {
                using (var data = NSData.FromUrl (imgUrl)) {
                    collectionData.Add (UIImage.LoadFromData (data));
                    downloadedPhotos++;
                    if (downloadedPhotos == totalPhotos) {
                        Console.WriteLine ("Finished downloading all photos");
                        InvokeOnMainThread (delegate {
                            photoSource.photos = collectionData;
                            PhotoCollection.ReloadData ();
                            Console.WriteLine("number of photos now "+ photoSource.photos.Count);
                        });
                    }
                }
            }

        }