private void KeyboardDevice_KeyDown(object sender, OpenTK.Input.KeyboardKeyEventArgs e)
        {
            var key = OpenTKHelpers.KeyToKeys(e.Key);

            KeyDown?.Invoke(this, new KeyEventArgs(KeyboardState.Empty, key, ' '));
        }
        private void KeyboardDevice_KeyUp(object sender, KeyboardKeyEventArgs e)
        {
            var key = OpenTKHelpers.KeyToKeys(e.Key);

            keys.Remove(key);
        }