Therefore, WS-BPEL claims that only one request-response operation per process instance may be active at any given time for each port type, operation, correlation set, and partner link.
Therefore, Business process Choreographer mandates that within one process instance at most one receive or pick activity or event handler may be active with the same port type and operation.
因此，Business Process Choreographer有如下强制要求：在一个流程实例内，最多一个具有相同端口类型和操作的接收或选择活动或者事件处理程序处于活动状态。