public override void WriteStartAttribute(string prefix, XmlDictionaryString localName, XmlDictionaryString namespaceUri)
 {
     CheckAsync();
     CoreWriter.WriteStartAttribute(prefix, localName, namespaceUri);
 }
 public override void WriteStartAttribute(string prefix, string localName, string ns)
 {
     CheckAsync();
     CoreWriter.WriteStartAttribute(prefix, localName, ns);
 }