anchor.diff:      }
     }
   
  +  @override
  +  void writeTo(StringBuffer buffer) {
  +    build().writeTo(buffer);
  +  }
  +
  +  @override
  +  void writePrettyTo(StringBuffer buffer, int level, String indent) {
  +    build().writePrettyTo(buffer, level, indent);
  +  }
  +
   }
   
   abstract class _XmlNodeBuilder {
  
positive.code:    */
    XmlNode build() => _stack.last.build();
  
    @override
    String toString() => build().toString();
  
    // Internal method to build a name.
    XmlName _buildName(String name, String uri) {
      return uri == null || uri.isEmpty
  
negative.code:  *
   * API is not finalized yet, do not use.
   */
  class XmlBuilder implements XmlWritable {
  
    final List<_XmlNodeBuilder> _stack = new List.from([new _XmlDocumentBuilder()]);
  
  