title: How to get User.Identity working outside controller
body: <p>I have separate project with some of my custom ASP.NET MVC helpers</p>
  
  <p>In one of my helpers I need to check user identity. </p>
  
  <p>How may I get <code>User.Identity</code> working there?</p>
  
  <p>By default it is living in <code>System.Security.Principal</code> in interface called <code>interface IPrincipal</code></p>