Swift中如何遍历一个类的所有属性？

import Foundation

struct Point {
    var x = 0.0
    var y = 0.0
}

class PropertyHub {
    var simpleProp = "Foo"
    var structProp = Point()

    // computed property is not visible in reflect().
    var computedProp : Point {
        get {
            return Point(x: structProp.x + 100.0, y: structProp.y - 100.0)
        }
    }
}

// we have to create an instance before calling reflect().
var hub = PropertyHub()

let mirror = reflect(hub)
let count = mirror.count

// this for loop will print:
//