This library was only ever intented to fill a temporary gap in functionality that existed in ASP.NET MVC, but had not quite made it to ASP.NET Core. That has now been addressed. As such I will no longer be maintaining this code base. Please consider using the official WsFed library here:
https://www.nuget.org/packages/Microsoft.AspNetCore.Authentication.WsFederation
This is a port of the Katana WsFederation middleware for ASP.NET Core. This project has a hard dependency on the full .NET Framework as many of the required BCL classes do not exist in the .NET Standard.
PM> Install-Package AspNetCore.Authentication.WsFederation