如何在NavigationPage中手动添加后退按钮？

<NavigationPage.TitleView>
    <StackLayout Orientation="Horizontal">
        <Button Text="后退" Clicked="OnBackButtonClicked" />
        <Label Text="导航栏标题" />
    </StackLayout>
</NavigationPage.TitleView>

private void OnBackButtonClicked(object sender, EventArgs e)
{
    Navigation.PopAsync();
}

var navigationPage = new NavigationPage(new YourPage());
MainPage = navigationPage;