title: When is HttpContext.User.Identity set?
body: <p>I have authentication code:</p>
  
  <pre><code>var authTicket = new FormsAuthenticationTicket(/*blahblah....*/);
  var cookie = new HttpCookie(FormsAuthentication.FormsCookieName, 
                              FormsAuthentication.Encrypt(authTicket));
  Response.Cookies.Add(cookie);
  var name = HttpContext.User.Identity.Name; // line 4
  </code></pre>
  
  <p>By putting in debug statements, I find that <code>name</code> on line 4 is empty.  But the next time I make a call on this browser session, the <code>HttpContext.User.Identity.Name</code> is correctly set.</p>
  
  <p>So when does this value get set?</p>