call

# File actionpack/lib/action_dispatch/middleware/cookies.rb, line 690
    def call(env)
      request = ActionDispatch::Request.new env

      status, headers, body = @app.call(env)

      if request.have_cookie_jar?
        cookie_jar = request.cookie_jar
        unless cookie_jar.committed?
          cookie_jar.write(headers)
          if headers[HTTP_HEADER].respond_to?(:join)
            headers[HTTP_HEADER] = headers[HTTP_HEADER].join("\n")
          end
        end
      end

      [status, headers, body]
    end