protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
renderer = new AndroidTreeRenderer <MainActivity>(
context: this,
CreateTree,
this,
attachChildToRoot: (r, c) => r.SetContentView(c),
detachChildFromRoot: (r, c) => r.SetContentView(null),
TaskScheduler.FromCurrentSynchronizationContext()
);
renderer.Render(NewState.Empty);
}