# File lib/aws/core/options/xml_serializer.rb, line 56
        def serialize request_options
          if http && http[:request_payload]
            payload = http[:request_payload]
            root_node_name = rules[payload][:name]
            params = request_options[payload]
            rules = self.rules[payload][:members]
          else
            root_node_name = "#{operation_name}Request"
            params = request_options
            rules = self.rules
          end
          xml = Nokogiri::XML::Builder.new
          xml.send(root_node_name, :xmlns => namespace) do |xml|
            hash_members_xml(params, rules, xml)
          end
          xml.doc.root.to_xml
        end