function getEventDescription(event) {
    var message = event.message, eventId = event.event_id;
    if (message) {
        return message;
    }
    var firstException = getFirstException(event);
    if (firstException) {
        if (firstException.type && firstException.value) {
            return firstException.type + ": " + firstException.value;
        }
        return firstException.type || firstException.value || eventId || '<unknown>';
    }
    return eventId || '<unknown>';
}
Extracts either message or type+value from an event that can be used for user-facing logs
@returns event's description