title: XmlWriter.WriteCData throws an ArgumentException - invalid character
body: <pre><code>StringBuilder output = new StringBuilder();
  using (XmlWriter writer = XmlWriter.Create(output))
  {
      writer.WriteStartElement("test");
      writer.WriteCData("taco\vbell");
      writer.WriteEndElement();
      writer.WriteEndDocument();
  }
  
  Console.WriteLine(output.ToString());
  </code></pre>
  
  <p>WriteCData throws the following ArgumentException, "'\v', hexadecimal value 0x0B, is an invalid character"</p>
  
  <p>I thought CData can take any kind of data.  Since this is not the case, what characters do I have to escape?  Thanks.</p>