测量SwiftUI视图的渲染大小？

import SwiftUI

struct ContentView: View {
    var body: some View {
        GeometryReader { geometry in
            VStack {
                Text("Hello, World!")
                    .font(.largeTitle)
                    .frame(width: geometry.size.width, height: geometry.size.height)
                
                Text("Width: \(geometry.size.width)")
                Text("Height: \(geometry.size.height)")
            }
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}