public function time($time, $precision = 0)
    {
        $units = 's';
        if ($time < 1e-6) {    // <1us
            $units = 'ns';
            $time *= 1e9;

        } elseif ($time < 1e-3) { // <1ms
            $units = "\xc2\xb5s";
            $time *= 1e6;

        } elseif ($time < 1) { // <1s
            $units = 'ms';
            $time *= 1e3;
        }

        return \round($time, $precision) . ' ' . $units;
    }