title: Overwriting root element in syndicationfeed, Adding namespaces to root element
body: <p>I need to add new namespaces to the rss(root) element of my feed, in addition to a10:</p>
  
  <pre><code>&lt;rss xmlns:a10="http://www.w3.org/2005/Atom" version="2.0"&gt;
      &lt;channel&gt;
  .
  .
  .
  </code></pre>
  
  <p>I am using a SyndicationFeed class serialized to RSS 2.0 and I use a XmlWriter to output the feed, </p>
  
  <pre><code>var feed = new SyndicationFeed(
                      feedDefinition.Title,
                      feedDefinition.Description,
       .
       .
       .
  
  
  
  using (var writer = XmlWriter.Create(context.HttpContext.Response.Output, settings))
          {
              rssFormatter.WriteTo(writer);
          }
  </code></pre>
  
  <p>I have tried adding AttributeExtensions on SyndicationFeed but it adds the new namespaces
  to the channel element instead of the root,</p>
  
  <p>Thank you </p>