Zumba\Swivel\Bucket::__construct PHP Метод

    public function __construct(MapInterface $featureMap, $index = null, LoggerInterface $logger = null, callable $callback = null)
    {
        $this->setLogger($logger ?: new NullLogger());
        $this->featureMap = $featureMap;
        $this->index = $index === null ? $this->randomIndex() : $index;
        $this->callback = !is_null($callback) ? $callback : function () {
        };
    }