ItemShipping, represents a shipping option for an Item.
- ShippingOptionId, OBSOLETE: Use ShippingProviderId instead.
- Cost, The cost (for the buyer) for shipping the item through the shipping option.
- ShippingWeight, The optional weight of the item when packed.
- ShippingProductId, The optional product id of the item when packed.
- ShippingProviderId, The numeric id for the shipping provider. See the method GetShippingOptions for a list of shipping providers and options.