Support for partial sales/delivery

[koapeadu]

Consider a case where a customer has back-ordered 100 tomatoes, and our supplier can only provide 50 tomatoes per week.
Since they are perishables, we will like to sell/deliver the first 50 as and when we receive it, and then deliver the next consignment when we receive it the next week.
So I suggest that we have a method like
$backOrderTransaction->soldPartial(50, 'Delivered only 50. Awaiting 50 in next consignment from supplier')