public function next()
    {
        $this->key++;
        if (\PDO::FETCH_COLUMN !== $this->fetchMode) {
            $this->current = $this->queryResult->fetch(
                    $this->fetchMode,
                    $this->driverOptions
            );
        } else {
            $this->current = $this->queryResult->fetchOne(
                    $this->driverOptions['columnIndex'] ?? 0
            );
        }
    }