posthog-js supports person.set_once but our backend doesn't. Make sure we can pass through `$set_once` on an `$identify` call, and only set the properties within if the properties aren't already set on the user.
ee/clickhouse/process_event.py
if data.get("timestamp"):
        if sent_at:
            
            
            try:
                
                
                return now + (parser.isoparse(data["timestamp"]) - sent_at)
            except TypeError as e:
                capture_exception(e)
        return parser.isoparse(data["timestamp"])
    now_datetime = now
    if data.get("offset"):
        return now_datetime - relativedelta(microseconds=data["offset"] * 1000)
    return now_datetime
if is_ee_enabled():
    def process_event_ee(