src/Printer.php
protected function writePerformance($time)
    {
        $ms = round($time * 1000);

        foreach (self::$performanceThresholds as $colour => $threshold) {
            if ($ms > $threshold) {
                break;
            }
        }

        $this->writeWithColor($colour, " ($ms ms)");
    }
protected function writePerformance($time)
    {
        $ms = round($time * 1000);

        foreach (self::$performanceThresholds as $colour => $threshold) {
            if ($ms > $threshold) {
                break;
            }
        }

        $this->writeWithColor($colour, " ($ms ms)");
    }
Writes the test performance metric formatted as the number of milliseconds elapsed.

@param float $time Number of seconds elapsed.