# File htree/display.rb, line 17
    def display_xml(out=$stdout, encoding=HTree::Encoder.internal_charset)
      encoder = HTree::Encoder.new(encoding)
      self.output(encoder, HTree::DefaultContext)
      # don't call finish_with_xmldecl because self already has a xml decl.
      out << encoder.finish
      out
    end