为tableviewdatasource添加列表而不是替换列表

我目前正在尝试添加分页到我的Instagram应用程序，并已设法取代列表，提供数据源与新数据，但我想将其添加到现有的列表，以便当我滚动回去它会显示最新的图片。以下是我目前的做法:

            var request = new RestRequest { RootElement = "data", Resource = "/users/self/feed" };
            request.AddParameter ("access_token", instagramAccessToken);
            var client = new RestClient ("https://api.instagram.com/v1");
            client.ExecuteAsync (request, response => {
                var rootObject = JsonConvert.DeserializeObject<RootObject> (response.Content);
                string nextURL = rootObject.pagination.next_url;
                //// Create Next Client
                var requestBack = new RestRequest ();
                var clientBack = new RestClient (nextURL);
                // GET Next Response
                clientBack.ExecuteAsync(requestBack, responseBack => {
                    var rootObjectBack = JsonConvert.DeserializeObject<RootObject> (responseBack.Content);
                    table.InvokeOnMainThread (() => {
                        // Create list that contains newly attained JSON
                        List<Datum> instagramData = rootObjectBack.data;
                        // Create dummy list for other values
                        List<Datum> sloppy = null;
                        // Send list that contains data, and the sloppy which doesnt contain anything to the Facebook and Twitter Values.
                        table.Source = new TableSource<Datum>(instagramData, sloppy, sloppy);
                        table.ReloadData ();
                    });
                });
            });