title: Extend AuthorizeAttribute Override AuthorizeCore or OnAuthorization
body: <p>Using ASP.NET MVC I am creating a custom Authorize attribute to take care of some custom authorization logic.  I have looked at a lot of examples and it is pretty straight forward but my question is which method is best to override, AuthorizeCore or OnAuthorization?  I have seen many examples overriding one or the other.  Is there a difference?  </p>