{
    "_type": str,  # message type
    "_type_spec": str,  # metric type
    "_data_ts": float,  # data timestamp
    "_data": {
        "measurement": str,  # metric type
        "tags": {
            "pipeline": str,
            "source": str,
            "roi_name": str,  # if applicable
            "class_name": str,  # if applicable
            "lc_name": str  # if applicable
        },
        "fields": {
            "val": int/float  # count or time, depending on metric
        },
        "time": int # time of message creation
    }
}