iOS动态派发 - 修改fileprivate属性

public class Demo : NSObject{
    @objc fileprivate var name = "123"
    
    
    func namePrint(){
        print(name)
    }
}

var demo = Demo()
demo.namePrint()//123

objc_setAssociatedObject(demo, "name", "321", objc_AssociationPolicy(rawValue: 3)!)
demo.namePrint()//123

demo.setValue("321", forKey: "name")
demo.namePrint()//321