Get active viewers for a session

{
    "success": true,
    "data": {
        "viewers": [
            {
                "id": "497f6eca-6276-4993-bfeb-53cbbbba6f08",
                "user_id": "a169451c-8525-4352-b8ca-070dd449a1a5",
                "username": "string",
                "joined_at": "2019-08-24T14:15:22.123Z",
                "role": "string"
            }
        ],
        "total": 0
    },
    "timestamp": 0
}