Xamarin.Mac custom controls, how do I add properties to display in the Xcode panel?

I want to implement custom controls, but the official case is too limited, I can not know more. What I want to know now is that I want to add an attribute to my control, such as Title, which must be free to fill in the Xcode control properties panel.

My current learning document: https://developer.xamarin.com/guides/mac/user-interface/custom-controls/

I refer to the IOS method, but didn't see the actual effect.

    [Export("Image"), Browsable(true)]
    public UIImage Image
    {
        get { return image; }
        set
        {
            image = value;
            SetNeedsDisplay();
        }
    }