title: Appending multiple segments with System.Uri
body: <pre><code>var baseUri = new Uri("http://localhost/");
  var uri1 = new Uri(baseUri, "1");
  var uri2 = new Uri(uri1, "2");   
  </code></pre>
  
  <p>Unexpectedly, <code>uri2</code> is <a href="http://localhost/2">http://localhost/2</a>. How would I append to <code>uri1</code> so it's <a href="http://localhost/1/2">http://localhost/1/2</a> intead? Does <code>Uri</code> do this, or do I need to fallback to strings? Incidentally, I've tried adding leading/trailing slashes almost everywhere.</p>