curl --request POST \
  --url https://realtime-api.voiceflow.com/v1/stable/test-turn \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "type": "user",
  "testID": "<string>",
  "payload": {
    "response": "<string>",
    "variableStates": "<string>"
  }
}
'

{
  "turn": {
    "id": "<string>",
    "testID": "<string>",
    "createdAt": "2023-11-07T05:31:56Z",
    "updatedAt": "2023-11-07T05:31:56Z",
    "type": "user",
    "payload": {
      "response": "<string>",
      "variableStates": "<string>"
    }
  }
}