title: Force XML serialization of XmlDefaultValue values
body: <p>Using a C# class generated from an XSD document, I can create an object, and serialize it successfully.  However, some attributes have an XmlDefaultValue defined.  If any objects have the default value, then those attributes do not get created when the object is serialized.  </p>
  
  <p>This is expected behavior according to the <a href="http://msdn.microsoft.com/en-us/library/system.xml.serialization.xmlattributes.xmldefaultvalue%28v=vs.110%29.aspx" rel="nofollow">documentation</a>.  But this is not how I want it to behave.  I need to have all such attributes generated in the XML document.<br>
  I've checked for any code attributes that can be applied that might force it to be outputted, even if it is the default value, but I couldn't find anything like that.</p>
  
  <p>Is there any way to make that work?</p>