如何在SwiftUI中禁用位置动画？

import SwiftUI

struct ContentView: View {
    @State private var showView = false

    var body: some View {
        VStack {
            Button(action: {
                withAnimation {
                    self.showView.toggle()
                }
            }) {
                Text("Toggle View")
            }

            if showView {
                Rectangle()
                    .fill(Color.blue)
                    .frame(width: 100, height: 100)
                    .animation(nil) // 禁用位置动画
            }
        }
    }
}

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