title: What is the first global.asax event that Session is accessible assuming the context handler is IRequiresSessionState or IReadOnlySessionState?
body: <p>My app sometimes calls <code>Server.Transfer</code> in the <code>Application_OnPostAuthenticateRequest</code> event of the global.asax to act as kind of url rewite.  When this happens and I need to access <code>Session</code> I get an HttpException: "Session state can only be used when enableSessionState is set to true..."  I am assuming this is happening because of the event I am calling <code>Server.Transfer</code>.  Is that why I am getting the exception?  When should I do the transfer?</p>