AIAssistantMessage(AIAssistantMessage)

{
    "id": "497f6eca-6276-4993-bfeb-53cbbbba6f08",
    "session_id": "1ffd059c-17ea-40a8-8aef-70fd0307db82",
    "role": "string",
    "content": "string",
    "tokens": 0,
    "created_at": "2019-08-24T14:15:22.123Z",
    "metadata": {
        "property1": "string",
        "property2": "string"
    }
}