# File lib/nokogiri/xml/node.rb, line 572
      def serialize *args, &block
        options = args.first.is_a?(Hash) ? args.shift : {
          :encoding   => args[0],
          :save_with  => args[1] || SaveOptions::FORMAT
        }

        encoding = options[:encoding] || document.encoding

        outstring = ""
        if encoding && outstring.respond_to?(:force_encoding)
          outstring.force_encoding(Encoding.find(encoding))
        end
        io = StringIO.new(outstring)
        write_to io, options, &block
        io.string
      end