title: How to map System Enum's in Protobuf.Net
body: <p>I have a class which has a property of type System.IO.FileAttribute (enum)</p>
  
  <p>Upon serializing with protobuf-net I get the error:</p>
  
  <pre><code>No wire-value is mapped to the enum System.IO.FileAttributes.Hidden, System, Archive
  </code></pre>
  
  <p>How would I go about mapping system enum's to a Contract with Members?</p>