title: Facebook location button through Dialogflow
body: <p>I'm currently developing a facebook messenger bot using dialogflow.
  I need to send the location button, on the facebook custom payload what i have to write?</p>
  
  <pre><code>   {
        "facebook": {
          "attachment": {
            "type": "",
            "payload": {}
          }
        }
      }
  </code></pre>
  
  <p>I have tried many thing but i can't figure it out
  Thanks a lot</p>