title: Can I assign a BaseUri to an XDocument?
body: <p>When I load an XML document from disk into an XDocument, that XDocument has a ready-only property BaseUri that contains the original XML document's location on disk.  In other words, </p>
  
  <pre><code>XDocument doc = XDocument.Load(@"c:\temp\doc.xml");
  Console.Out.WriteLine(doc.BaseUri);
  // Outputs "file:///c:/temp/doc.xml"
  </code></pre>
  
  <p>If I create a new XDocument from scratch, it has no BaseUri.  For example:</p>
  
  <pre><code>XDocument doc = new XDocument(new XElement("test"));
  Console.Out.WriteLine(doc.BaseUri);
  // Outputs nothing
  </code></pre>
  
  <p>Can I assign this new XDocument a BaseUri?  I'd like to be able to generate new documents, assign them names, and easily pass those names along with them.</p>