xcode - 为什么 UIViewRepresentable 的 makeUIView 和 updateUIView 被调用了这么多次 xcode Playground？

Question

我有一个简单的 SwiftUI 包装，带有 UIKit 作为 Playground 上的显示（使用 Xcode 12.1）

import UIKit
import PlaygroundSupport
import SwiftUI

struct ContentView: View {

    var body: some View {
        WrapView()
    }
}

struct WrapView: UIViewRepresentable {
    func makeUIView(context: Context) -> UIView {
        print("makeUIView")
        return UIView(frame: .infinite)
    }
    func updateUIView(_ uiView: UIView, context: Context) {
        print("updateUIView")
    }
}

PlaygroundPage.current.setLiveView(ContentView())

看到这么多电话，我很惊讶，makeUIView如下updateUIView所示

makeUIView
updateUIView
makeUIView
updateUIView
makeUIView
updateUIView
makeUIView
updateUIView
updateUIView
updateUIView
updateUIView
updateUIView