public override bool IsSet(string key)
 {
     if (nfo.ContainsProperty(key))
     {
         if (!ignoreUnspecified || !nfo.IsDefaultValue(userObject, key))
         {
             return(true);
         }
     }
     if (extra != null)
     {
         if (extra.ContainsKey(key))
         {
             return(true);
         }
     }
     return(false);
 }