SwiftUI:如何在预览过程中更改顶级ContentView @状态？

import SwiftUI

struct ContentView: View {
    @State private var isToggled = false
    
    var body: some View {
        VStack {
            Text("Hello World")
                .font(.title)
                .foregroundColor(isToggled ? .green : .red)
            
            Button(action: {
                self.isToggled.toggle()
            }) {
                Text("Toggle")
                    .padding()
                    .background(Color.blue)
                    .foregroundColor(.white)
                    .cornerRadius(10)
            }
        }
    }
}

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