Esri.ArcGISRuntime.Layers C# Can't access this namespace, which package do I need?

[SquarecodeDeveloper]

I want to use this namespace because I want access to the ArcGISTiledMapServiceLayer class. I have included Esri.ArcGISRuntime and Esri.ArcGISRuntime.Xamarin.Form (version 100.9) from nuget in my project.

The error message I get is

CS0234: The type or namespace name 'Layers' does not exist in the namespace 'Esri.ArcGISRuntime' (are you missing an assembly rederence?)

Is there another nuget package I also need to include?

The error

My nuget

I am trying to work off this example Create an offline app—ArcGIS Runtime SDK for .NET | ArcGIS for Developers 

[JoeHershman]

That sample is from the older Runtime API (version 10.x).  This would be a link to the current API OfflineMapTask Class 

See ArcGIS Runtime SDK for .NET (latest) | ArcGIS for Developers  for top level site