Is it possible to use an external Identity Provider in a Web API with ASP.NET 5?

Reading this question, @Pinpoint’s answer and the further discussion on comments, I’m well aware that natively we can’t add an identity provider to our apps developed with ASP.NET 5. One possible replacement for the legacy OAuthAuthorizationServerMiddleware is then provided by the AspNet.Security.OpenIdConnect.Server as I’ve found in many places.