Serial plugin - which uses product SKU, User Name and date of order

Hi Guys,

so I have look on existed plugins of HikaSerial, and as far as I see,
any of this plugin use information from User/Product/Order.

Our serial-gen algorithm uses:
- Company name if specified, else UserName
- Order Date - to produce serial with encoded date
- SKU of product/variant to define with its help OS and product.

First of all, I have try to log values of params.

public function generate(&$pack, &$order, $quantity, &$serials) 
{
	error_log( "order_id = $order->order_id"  );

$orderClass = hikashop_get('class.order');
$orderClass->loadProducts( $order->order_id );
foreach( $order->products as $k => $product ) 
{
	error_log( "product_id = $product->product_id" );
	error_log( "product_name = $product->product_name" );
}