Accounting::compileHash

private function compileHash(Item $item): string
{
	$ownerHash = serialize($item->getData());

	$productRows = $item->getProductRows() ? $item->getProductRows()->toArray() : [];
	$productRowsHash = serialize($productRows);

	// return result from cache only if a current item is exactly the same as previous
	return md5($ownerHash . $productRowsHash);
}