title: Create ETag filter in ASP.NET MVC
body: <p>I would like to create an ETag filter in MVC.
  The problem is that I can't control the Response.OutputStream, if I was able to do that I would simply calculate the ETag according to the result stream.
  I did this thing before in WCF but couldn't find any simple idea to do that in MVC.</p>
  
  <p>I want to be able to write something like that</p>
  
  <pre><code>[ETag]
  public ActionResult MyAction()
  {
      var myModel = Factory.CreateModel();
      return View(myModel);
  }
  </code></pre>
  
  <p>Any idea?</p>