// Discovery stream returned
        private void OnDiscoveryStreamReturned(object sender, GetDiscoveryStreamEventArgs e)
        {
            JObject rawJson = JObject.Parse(e.Response);
            JObject rootJson = (JObject)rawJson["photos"];
            TotalDiscoveryPhotosCount = int.Parse(rootJson["total"].ToString());
            int page = int.Parse(rootJson["page"].ToString());
            int numPages = int.Parse(rootJson["pages"].ToString());
            int perPage = int.Parse(rootJson["perpage"].ToString());

            List<Photo> newPhotos = new List<Photo>();
            foreach (var entry in rootJson["photo"])
            {
                JObject json = (JObject)entry;
                Photo photo = PhotoFactory.PhotoWithJObject(json);

                if (!DiscoveryList.Contains(photo))
                {
                    DiscoveryList.Add(photo);
                    newPhotos.Add(photo);
                }
            }

            // Dispatch event
            DiscoveryStreamUpdatedEventArgs args = new DiscoveryStreamUpdatedEventArgs();
            args.Page = page;
            args.PageCount = numPages;
            args.PerPage = perPage;
            args.NewPhotos = newPhotos;
            DiscoveryStreamUpdated.DispatchEvent(this, args);
        }
        public async void GetDiscoveryStreamAsync(Dictionary<string, string> parameters = null)
        {
            IsLoadingDiscoveryStream = true;

            string timestamp = DateTimeUtils.GetTimestamp();
            string nonce = Guid.NewGuid().ToString().Replace("-", null);

            Dictionary<string, string> paramDict = new Dictionary<string, string>();
            paramDict["method"] = "flickr.interestingness.getList";
            paramDict["format"] = "json";
            paramDict["nojsoncallback"] = "1";
            paramDict["oauth_consumer_key"] = consumerKey;
            paramDict["oauth_nonce"] = nonce;
            paramDict["oauth_signature_method"] = "HMAC-SHA1";
            paramDict["oauth_timestamp"] = timestamp;
            paramDict["oauth_token"] = AccessToken;
            paramDict["oauth_version"] = "1.0";

            if (parameters != null)
            {
                foreach (var entry in parameters)
                {
                    paramDict[entry.Key] = entry.Value;
                }
            }

            paramDict["extras"] = UrlHelper.Encode(commonExtraParameters);
            string paramString = GenerateParamString(paramDict);
            string signature = GenerateSignature("GET", AccessTokenSecret, "https://api.flickr.com/services/rest", paramString);
            string requestUrl = "https://api.flickr.com/services/rest?" + paramString + "&oauth_signature=" + signature;
            HttpWebResponse response = await DispatchRequest("GET", requestUrl, null).ConfigureAwait(false);
            using (StreamReader reader = new StreamReader(response.GetResponseStream()))
            {
                IsLoadingDiscoveryStream = false;

                if (response.StatusCode != HttpStatusCode.OK)
                {
                    HandleHTTPException(response);
                    DiscoveryStreamException(this, null);
                    return;
                }

                string jsonString = await reader.ReadToEndAsync().ConfigureAwait(false);
                if (!TryHandleResponseException(jsonString, () => { GetDiscoveryStreamAsync(parameters); }))
                {
                    DiscoveryStreamException(this, null);
                    return;
                }


                GetDiscoveryStreamEventArgs args = new GetDiscoveryStreamEventArgs();
                args.Response = jsonString;
                DiscoveryStreamReturned.DispatchEvent(this, args);
            }
        }