title: Render pubDate with RSS SyndicationFeed api
body: <p>I am trying to serve an RSS feed from my ASP.net MVC site. Everything is working accept for the pubdate element. I can't seem to get the Rss20FeedFormatter to output it. I thought that it maps to the LastUpdatedDate property on the SyndicationFeed object, but that outputs as LastBuildDate. </p>
  
  <p>Does anyone know how I can use the SyndicationFeed with Rss20FeedFormatter to render the pubDate node in my RssFeed?</p>
  
  <pre><code>   public class RssActionResult : ActionResult
      {
          public SyndicationFeed Feed { get; set; }
          public override void ExecuteResult(ControllerContext context)
          {
              context.HttpContext.Response.ContentType = "application/rss+xml";
              var rssFormatter = new Rss20FeedFormatter(Feed, false);
              using (var writer = XmlWriter.Create(context.HttpContext.Response.Output, new XmlWriterSettings{ Indent = true}))
                  rssFormatter.WriteTo(writer);
          }
      }
  </code></pre>
  
  <p>example of how I am creating the feed.</p>
  
  <pre><code>new SyndicationFeed("Title", "Description", url, "test_id", publishDate, feedItems){ LastUpdatedTime = publishDate}
  </code></pre>