Native Forms on Android

I am trying to experiment with Native Forms in XF. I have this in iOS working right. That is fine.

In Android, I am getting the following error:

'MainPage' does not contain a definition for 'CreateSupportFragment' and the best extension method overload 'PageExtensions.CreateSupportFragment(ContentPage, Context)' requires a receiver of type 'ContentPage'

The code is erroring in the following code:
var _cp = new MainPage(); // my page from XF.
_list = _cp.CreateSupportFragment(this);

I have made sure that my nuget packages are up to date. I have cleaned and compiled. I've done a bunch of things, but alas, no love. Any ideas on this?

TIA