LoginViewController.cs

public partial class LoginViewController : UIViewController
{
  private ILoginPresenter _loginPresenter = null;
  private IAsyncSubscriber _listenerToken = null;
  
  public override void ViewDidLoad()
  {
    base.ViewDidLoad();
    
    // Load presenter
    _loginPresenter = DependencyService.Instance.LoadService<ILoginPresenter>();
    
    _listenerToken = _loginPresenter.StartListening(
      () => 
      {
        // Show loading state
        SetProgressVisible(true);
      },
      () =>
      {
        // Show delay in loading, network delay
        ShowDelayedLabel(true);
      },
      () =>
      {
        // Clear fields
        ClearField(_userName);
        ClearField(_password);
      },
      async () =>
      {
        // Finger print requested
        await TransitionToFingerprintScreen();
      },
      async () => 
      {
        // Show quick passcode
        await TransitionToPasscode();
      },
      async () =>
      {
        // Show login
        await ShowLoginView();
      }
  }
  
  private void ClearServices()
  {
    // Clear out any references
    _listenerToken.StopListening();
  }
}