/// <summary>
        /// Allows the game to run logic such as updating the world,
        /// checking for collisions, gathering input, and playing audio.
        /// </summary>
        /// <param name="gameTime">Provides a snapshot of timing values.</param>
        protected override void Update(GameTime gameTime)
        {
            // For Mobile devices, this logic will close the Game when the Back button is pressed
            // Exit() is obsolete on iOS
#if !__IOS__ && !__TVOS__
            if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed ||
                Keyboard.GetState().IsKeyDown(Keys.Escape))
            {
                Exit();
            }
#endif
            if (_currentState.Initialised)
            {
                _currentState.Update(this, gameTime);
            }
            else
            {
                _currentState.Initialise(this);
            }
            base.Update(gameTime);
            InputHandler.Update();
        }