xamarin IEnumerator function never run

Question

I am new to c#, building an android/iOS app. I have a IEnumerator function called at my activity OnCreate() . But it never be called to execute.

        private ICoroutine _startCoroutine;
        protected override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);
            SetContentView(Resource.Layout.activity_main);
            this._startCoroutine = CoroutineManager.Default.StartCoroutine(this.Start2());this
        }

        private IEnumerator Start2()
        {
           // things to do
        }

I set a break point inside start(), but never trigged. What's the problem I have?

---

CoroutineManager

    public sealed class CoroutineManager
    {
        public static CoroutineManager Default
        {
            get
            {
                return Coroutine;
            }
        }
        public void StartCoroutine(IEnumerator routine)
        {
            if (routine == null)
            {
                throw new ArgumentNullException("routine");
            }
            StartCoroutine(routine);
        }
    }

Answer 1

Just create an example and it works:

public class MainActivity : AppCompatActivity
{
    protected override void OnCreate(Bundle savedInstanceState)
    {
        base.OnCreate(savedInstanceState);
        Xamarin.Essentials.Platform.Init(this, savedInstanceState);
        SetContentView(Resource.Layout.activity_main);

        CoroutineManager manager = new CoroutineManager();
        manager.StartCoroutine(this.Start2());
    }


    private IEnumerator Start2()
    {
        Console.WriteLine("Start2");
        ArrayList arr = new ArrayList();
        return arr.GetEnumerator();
    }
}

public class CoroutineManager
{
    public CoroutineManager()
    {

    }

    public void StartCoroutine(IEnumerator routine)
    {
        if (routine == null)
        {
            throw new ArgumentNullException("routine");
        }
        //StartCoroutine(routine);
    }
}