private void CreateItem(string text)
        {
            Task task = new Task {
                Title = text
            };

            AppDelegate.AddActivity();

            this.service.Tasks.Insert(task, this.list.Id).FetchAsync(lr => {
                AppDelegate.FinishActivity();

                Refresh();
            });
        }
        private void OnTap(Task task)
        {
            AppDelegate.AddActivity();

            bool completing = (task.Status != "completed");

            task.Status    = (completing) ? "completed" : "needsAction";
            task.Completed = (completing) ? XmlConvert.ToString(DateTime.Now, "yyyy-MM-ddTHH:mm:sszzzzzz") : null;

            this.service.Tasks.Update(task, this.list.Id, task.Id)
            .FetchAsync(lr => {
                Refresh();
                AppDelegate.FinishActivity();
            });
        }
        private void CreateList(string name)
        {
            if (String.IsNullOrWhiteSpace(name))
            {
                return;
            }

            AppDelegate.AddActivity();

            this.service.Tasklists.Insert(new TaskList {
                Title = name
            })
            .FetchAsync(lr => {
                TaskList result = lr.GetResult();

                AppDelegate.FinishActivity();

                BeginInvokeOnMainThread(() => {
                    var tasks = new TasksViewController(this.service, result);
                    NavigationController.PushViewController(tasks, animated: true);
                });
            });
        }
        private void Refresh()
        {
            AppDelegate.AddActivity();

            this.service.Tasks.List(list.Id).FetchAsync(OnListTasks);
        }
        private void Refresh()
        {
            AppDelegate.AddActivity();

            this.service.Tasklists.List().FetchAsync(OnTaskListResponse);
        }