struct Event
{
    EventType type = EventType.T_EV_None;
    int num_elements;
    @property joystickButton()
    {
        enforce(type == EventType.T_EV_Input_JoystickButton);
        return cast(JoystickButton*)(&this);
    }
    @property appClose()
    {
        enforce(type == EventType.T_EV_ExitSession);
        return cast(AppClose*)(&this);
    }
}