/// <summary>
        /// The constructor is private: loading screens should
        /// be activated via the static Load method instead.
        /// </summary>
        private LoadingScreen( 
            /*ScreenManager screenManager,*/
            bool loadingIsSlow,
            Screen[] screensToLoad)
        {
            this.loadingIsSlow = loadingIsSlow;
            this.screensToLoad = screensToLoad;

            TransitionOnTime = TimeSpan.FromSeconds(1.5);
        }
        public static void Pop(Screen name)
        {
            if (isInitialized)
                name.UnloadContent();

            Stack.Remove(name);
            screensToUpdate.Remove(name);
        }
        public static void Switch(Screen name)
        {
            if (Stack.Count > 0)
            {
                Pop(name);

                Push(name);
            }
        }
        public static void Push(Screen name)
        {
            //name.ScreenManager = this;
            name.IsExiting = false;

            if (isInitialized)
                name.LoadContent();

            Stack.Add(name);
        }