title: Guard ArgumentNotNull - what is the argumentName parameter for?
body: <p>In an MVC project we use Unity's Guard.ArgumentNotNull method to check for null parameters in the constructor. I think this is quite a common practise. Could anyone tell me what the second parameter - argumentName - in this method is for? Surely if the project compiles it means that the argument has been named correctly? I've tried changing this string name to something else and it doesn't throw an error.</p>
  
  <p><code>Guard.ArgumentNotNull(userRoleProvider, "userRoleProvider");</code></p>