def init_original_response(self):
        """Get the original response for comparing, confirm is_cookie_necessary"""
        no_cookie_resp = None
        self.is_cookie_necessary = True
        if 'json' in self.request:
            self.request['data'] = json.dumps(self.request.pop('json')).encode(
                self.encoding)
        r1 = self.req.request(
            retry=self.retry, timeout=self.timeout, **self.request)
        if 'headers' in self.request:
            # test is_cookie_necessary
            cookie = self.request['headers'].get('Cookie', None)
            if cookie:
                new_request = deepcopy(self.request)
                new_request['headers']['Cookie'] = ''
                r2 = self.req.request(
                    retry=self.retry, timeout=self.timeout, **new_request)
                no_cookie_resp = self.ensure_response(r2)
        resp = r1.x
        assert resp, ValueError(
            'original_response should not be failed. %s' % self.request)
        self.original_response = self.ensure_response(r1)
        self.encoding = self.encoding or resp.encoding
        if no_cookie_resp == self.original_response:
            self.ignore['headers'].append('Cookie')
            self.is_cookie_necessary = False
        return self.original_response