Magento 2: in depth of magento core [duplicate]

Question

Digging in magento core code I found some interesting code: https://github.com/magento/magento2/blob/develop/lib/internal/Magento/Framework/ObjectManager/Factory/AbstractFactory.php#L93

protected function createObject($type, $args)
{
    switch (count($args)) {
        case 1:
            return new $type($args[0]);
        case 2:
            return new $type($args[0], $args[1]);
        case 3:
            return new $type($args[0], $args[1], $args[2]);
        case 4:
            return new $type($args[0], $args[1], $args[2], $args[3]);
        case 5:
            return new $type($args[0], $args[1], $args[2], $args[3], $args[4]);
        case 6:
            return new $type($args[0], $args[1], $args[2], $args[3], $args[4], $args[5]);
        case 7:
            return new $type($args[0], $args[1], $args[2], $args[3], $args[4], $args[5], $args[6]);
        case 8:
            return new $type($args[0], $args[1], $args[2], $args[3], $args[4], $args[5], $args[6], $args[7]);
        case 9:
            return new $type(
                $args[0], $args[1], $args[2], $args[3], $args[4], $args[5], $args[6], $args[7], $args[8]
            );
        case 10:
            return new $type(
                $args[0], $args[1], $args[2], $args[3], $args[4], $args[5], $args[6], $args[7], $args[8], $args[9]
            );
        case 11:
            return new $type(
                $args[0],
                $args[1],
                $args[2],
                $args[3],
                $args[4],
                $args[5],
                $args[6],
                $args[7],
                $args[8],
                $args[9],
                $args[10]
            );
        case 12:
            return new $type(
                $args[0],
                $args[1],
                $args[2],
                $args[3],
                $args[4],
                $args[5],
                $args[6],
                $args[7],
                $args[8],
                $args[9],
                $args[10],
                $args[11]
            );
        case 13:
            return new $type(
                $args[0],
                $args[1],
                $args[2],
                $args[3],
                $args[4],
                $args[5],
                $args[6],
                $args[7],
                $args[8],
                $args[9],
                $args[10],
                $args[11],
                $args[12]
            );
        case 14:
            return new $type(
                $args[0],
                $args[1],
                $args[2],
                $args[3],
                $args[4],
                $args[5],
                $args[6],
                $args[7],
                $args[8],
                $args[9],
                $args[10],
                $args[11],
                $args[12],
                $args[13]
            );
        case 15:
            return new $type(
                $args[0],
                $args[1],
                $args[2],
                $args[3],
                $args[4],
                $args[5],
                $args[6],
                $args[7],
                $args[8],
                $args[9],
                $args[10],
                $args[11],
                $args[12],
                $args[13],
                $args[14]
            );
        default:
            $reflection = new \ReflectionClass($type);
            return $reflection->newInstanceArgs($args);
    }
}

What purpose for such awful code? Why can't we use reflection for less then 15 args like in default section?

Answer 1

because its faster if its explicit and above 15 seams to be rare, so in most cases it will be fast