private async Task <List <AdvancedTweet> > GetTimelineByUrl(string requestUrl)
        {
            OAuthClient         client   = new OAuthClient(accessToken);
            HttpResponseMessage response = new HttpResponseMessage();

            try
            {
                response = await client.GetAsync(requestUrl);
            }
            catch (Exception ex)
            {
                throw new Exception("ネットワークエラーでタイムラインを取得できません", ex);
            }

            if (response.IsSuccessStatusCode)
            {
                var json = await response.Content.ReadAsStringAsync();

                return(MyJsonConverter.DeserializeTweets(json, accessToken));
            }
            else
            {
                throw new Exception("レスポンスメッセージのStatusCodeがSuccessではありません。");
            }
        }
        public async Task <ObservableCollection <UserAccessToken> > GetUserListFromTweets(string requestUrl)
        {
            OAuthClient         client   = new OAuthClient(accessToken);
            HttpResponseMessage response = new HttpResponseMessage();
            ObservableCollection <UserAccessToken> userAccessTokens = new ObservableCollection <UserAccessToken>();

            try
            {
                response = await client.GetAsync(requestUrl);
            }
            catch (Exception ex)
            {
                var dialog = new MessageDialog(ex.Message, "ユーザー一覧を取得できません");
                await dialog.ShowAsync();
            }

            if (response.IsSuccessStatusCode)
            {
                var json = await response.Content.ReadAsStringAsync();

                List <AdvancedTweet> tweets = MyJsonConverter.DeserializeTweets(json, accessToken);
                foreach (var tweet in tweets)
                {
                    var item = new UserAccessToken(accessToken, tweet.source.user);
                    userAccessTokens.Add(item);
                }
                return(userAccessTokens);
            }
            else
            {
                var dialog = new MessageDialog(response.ReasonPhrase, "レスポンスメッセージのStatusCodeがSuccessではありません。");
                await dialog.ShowAsync();
            }
            return(null);
        }