{
  "event": "addDevice",
  "payload": {
    "id": "of:0000000000003333",
    "type": "virtual",
    "online": true,
    "master": "foo",
    "labels": [
      "",
      "cord",
      "of:0000000000003333"
    ],
    "metaUi": {
      "x": 200,
      "y": 400
    }
  }
}