Centering a page title

        public App ()
        {
            // The root page of your application
            MainPage = new NavigationPage(new Test.MainPage());
        }

        public MainPage ()
        {
            InitializeComponent ();

            Title = "Testttt";
           }

The title is left justified and hugs the back button. Should it not be centered by default, or at least allow to choose justification?