Received

{
  "sender":{
    "id":"USER_ID"
  },
  "recipient":{
    "id":"PAGE_ID"
  },
  "timestamp":1458692752478,
  "message":{
    "mid":"mid.1457764197618:41d102a3e1ae206a38",
    "text":"hello, world!",
    "quick_reply": {
      "payload": "DEVELOPER_DEFINED_PAYLOAD"
    }
  }
}