private function writeDefaultRowHeight()
    {
        $defaultRowHeight = $this->phpSheet->getDefaultRowDimension()->getRowHeight();

        if ($defaultRowHeight < 0) {
            return;
        }

        // convert to twips
        $defaultRowHeight = (int) 20 * $defaultRowHeight;

        $record = 0x0225; // Record identifier
        $length = 0x0004; // Number of bytes to follow

        $header = pack('vv', $record, $length);
        $data = pack('vv', 1, $defaultRowHeight);
        $this->append($header . $data);
    }