title: ClosedXML. Adding DataTable to existing Excel worksheet
body: <p>How using <a href="http://closedxml.codeplex.com/" rel="nofollow">ClosedXML</a> library in fastest way (from performance point of view) add values from <code>DataTable</code> to already existing Excel worksheet?</p>
  
  <p>NOTE: There is way to create new worksheet with <code>DataTable</code> parameter, but the main issue is in adding values to existing worksheet.</p>