[AttributeUsage(AttributeTargets.Method)]
    private class GUIEffect : Attribute
    {
        public void PerformCall(Action action)
        {
            action.Invoke();
            //action.somehowGetThis.UpdateGUI()
        }
    }

    [AttributeUsage(AttributeTargets.Method)]
    private class GUIEffect : Attribute
    {
        public void PerformCall(Action action)
        {
            action.Invoke();
            //action.somehowGetThis.UpdateGUI()
        }
    }