Node.js 如何使用dialogflow和外部webhook向facebook messenger发送通用模型的旋转木马？

我已经配置了一些步骤，如果我直接从webhook发送简单的答案，那么一切都会很完美。但是，如果我尝试使用有效负载发送旋转木马，webhook的响应不会到达messenger中的最终用户，因此返回我在dialogflow控制台中配置的标准响应

function list_news(agent) {
    console.log("\n\n\n", agent, "\n\n\n")
    //agent.add("DEFAULT RESPONSE TO " + agent.requestSource + " FROM WEBHOOK");
    const payload = {
      "facebook": {
        "attachment": {
          "type": "template",
          "payload": {
            "template_type": "generic",
            "elements": [
              {
                "title": "Machine Learning For Dummies (English Edition)",
                "image_url": "https://firebasestorage.googleapis.com/v0/b/universidade-qnej.appspot.com/o/livros%2FMachineLearning.jpg?alt=media&token=01ec5e95-d9ae-4f49-994e-f3c9d8a31405",
                "subtitle": "It's the best book for beginners!",
                "default_action": {
                  "type": "web_url",
                  "url": "https://www.amazon.com.br/AWS-CCP-Certified-Cloud-Practitioner-ebook/dp/B07JL64332/ref=sr_1_1?ie=UTF8&qid=1541085590&sr=8-1&keywords=aws+ccp",
                  "webview_height_ratio": "compact"
                },
                "buttons": [
                  {
                    "type": "web_url",
                    "url": "https://www.amazon.com.br/",
                    "title": "View Website"
                  }
                ]
              },
              {
                "title": "Machine Learning For Dummies (English Edition)",
                "image_url": "https://firebasestorage.googleapis.com/v0/b/universidade-qnej.appspot.com/o/livros%2FMachineLearning.jpg?alt=media&token=01ec5e95-d9ae-4f49-994e-f3c9d8a31405",
                "subtitle": "It's the best book for beginners!",
                "default_action": {
                  "type": "web_url",
                  "url": "https://www.amazon.com.br/AWS-CCP-Certified-Cloud-Practitioner-ebook/dp/B07JL64332/ref=sr_1_1?ie=UTF8&qid=1541085590&sr=8-1&keywords=aws+ccp",
                  "webview_height_ratio": "compact"
                },
                "buttons": [
                  {
                    "type": "web_url",
                    "url": "https://www.amazon.com.br/",
                    "title": "View Website"
                  }
                ]
              }
            ]
          }
        }
      }
    }
    agent.add(new Payload('FACEBOOK', payload, {sendAsMessage: true}));
  }

您可以参考一个关于如何使用Dialogflow Fulfillment添加富消息的示例，还建议共享与此响应相关的日志，以了解您的响应未返回的原因。