如何在SwiftUI中隐藏导航后退按钮？

struct CustomBackButton: View {
    var body: some View {
        Image(systemName: "chevron.left")
            .foregroundColor(.blue)
    }
}

struct ContentView: View {
    var body: some View {
        NavigationView {
            VStack {
                Text("Hello World!")
            }
            .navigationBarBackButtonHidden(true)
            .navigationBarItems(leading: CustomBackButton())
        }
    }
}