# File lib/typhoeus/response/informations.rb, line 47
      def response_headers
        return options[:response_headers] if options[:response_headers]
        if mock? && h = options[:headers]
            status_code = return_code || "200"
            reason_phrase = status_code == "200" ? "OK" : "Mock Reason Phrase"
            status_line = "HTTP/1.1 #{status_code} #{reason_phrase}"
            actual_headers = h.map{ |k,v| [k, v.respond_to?(:join) ? v.join(',') : v] }.
              map{ |e| "#{e.first}: #{e.last}" }

            [status_line, *actual_headers].join("\r\n")
        end
      end