title: Refresh entity instance with DbContext
body: <p>With EF4 CTP5 DbContext, what is the equivalent of this</p>
  
  <pre><code>    public void Refresh(Document instance)
      {
          _ctx.Refresh(RefreshMode.StoreWins, instance);
      }
  </code></pre>
  
  <p>I've tried this but it doesn't do the same thing, updating the instance</p>
  
  <pre><code>    public void Refresh(Document instance)
      {
          _ctx.ChangeTracker.DetectChanges();
      }
  </code></pre>
  
  <p>?</p>