protected function projectList(ItemList $list)
    {
        $sth = $list->deliverQueryObject()->execute();

        foreach ($sth as $row) {
            $listResult = $list->getResult($row);
            $object = $this->getObjectFromListResult($list, $listResult);
            yield iterator_to_array($this->projectObject($object));
            $this->tick();
        }
    }