如何在SwiftUI中根据其子高度设置GeometryReader的高度？

import SwiftUI

struct ContentView: View {
    var body: some View {
        GeometryReader { geometry in
            VStack {
                Text("Hello, SwiftUI!")
                    .font(.largeTitle)
                    .frame(maxWidth: .infinity)
                    .background(Color.green)
                
                // 子视图
                CustomSubview()
                    .background(Color.blue)
                    // 将子视图的frame传递给GeometryReader的frame
                    .frame(height: geometry.size.height * 0.5)
            }
            // 根据子视图的高度调整GeometryReader的高度
            .frame(height: geometry.size.height * 0.5)
        }
    }
}

struct CustomSubview: View {
    var body: some View {
        Text("I'm a custom subview")
            .font(.title)
            .foregroundColor(.white)
    }
}

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