How to exit an Android app programmatically?

Question

I am sure this question has been asked number of times because I read a few. My client wants me to put a button into his app where users can click and exit. I have read this

Answer 1

Achieving in Xamarin.Android:

    public override void OnBackPressed()
    {
        MoveTaskToBack(true);
        Process.KillProcess(Process.MyPid());
        Environment.Exit(1);
    }