final public static function dateSqlUtcToIsoOffset($date, $default = null)
    {
        if (!empty($date)) {
            $date = self::asDateTime($date);
            $date->setTimezone(self::tzUtc());
            return $date->format("Y-m-d\TH:i:sP");
        } else {
            return $default;
        }
    }