title: Parsing xml string to an xml document fails if the string begins with <?xml... ?> section
body: <p>I have an XML file begining like this:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;Report xmlns:rd="http://schemas.microsoft.com/SQLServer/reporting/reportdesigner" xmlns="http://schemas.microsoft.com/sqlserver/reporting/2008/01/reportdefinition"&gt;
    &lt;DataSources&gt;
  </code></pre>
  
  <p>When I run following code:</p>
  
  <pre><code>byte[] fileContent = //gets bytes
              string stringContent = Encoding.UTF8.GetString(fileContent);
              XDocument xml = XDocument.Parse(stringContent);
  </code></pre>
  
  <p>I get following XmlException:</p>
  
  <blockquote>
    <p>Data at the root level is invalid.
    Line 1, position 1.</p>
  </blockquote>
  
  <p>Cutting out the version and encoding node fixes the problem. Why? How to process this xml correctly?</p>