The orderer must then be prepared to respond to a request ( callback, in this case) to process the final invoice. 订货方然后必须响应一个请求(在本例中是回叫)来处理最终的货物。
Calculating the initial and final price for an invoice involves a slightly more complex protocol between an orderer and invoicer. 为发货单计算初始的和最终的价格,涉及到订货者和货品计价之间一个更加复杂的协议。