How can I create a response with rich messages in Dialogflow?

Currently, When an intent is invoked, I am calling a webhook and getting a response from the web service as json structure show below.

{
  "speech": "this text is spoken out loud if the platform supports voice interactions",
  "displayText": "this text is displayed visually"
}

This is mere text. Alternatively, What response do I have to get to display a list for example.

I tried the rich message section of dialogflow documentation. Those structures didn't work.

To add an Actions on Google List as part of the reply, you'll need to use the data field in your response to include a richResponse with what should be said, along with a systemIntent that contains the list information.

You can see more examples at their github example repository, but here is the one for showing a list:

{
  "data": {
    "google": {
      "expectUserResponse": true,
      "richResponse": {
        "items": [
          {
            "simpleResponse": {
              "textToSpeech": "Choose an item"
            }
          }
        ]
      },
      "systemIntent": {
        "intent": "actions.intent.OPTION",
        "data": {
          "@type": "type.googleapis.com/google.actions.v2.OptionValueSpec",
          "listSelect": {
            "title": "Hello",
            "items": [
              {
                "optionInfo": {
                  "key": "first title"
                },
                "description": "first description",
                "image": {
                  "url": "https://developers.google.com/actions/images/badges/XPM_BADGING_GoogleAssistant_VER.png",
                  "accessibilityText": "first alt"
                },
                "title": "first title"
              },
              {
                "optionInfo": {
                  "key": "second"
                },
                "description": "second description",
                "image": {
                  "url": "https://lh3.googleusercontent.com/Nu3a6F80WfixUqf_ec_vgXy_c0-0r4VLJRXjVFF_X_CIilEu8B9fT35qyTEj_PEsKw",
                  "accessibilityText": "second alt"
                },
                "title": "second title"
              }
            ]
          }
        }
      }
    }
  }
}