When a given block needs input from multiple sources, it will wait until all sources have data available.
当某个块需要接收多个源的输入时，它会等待，直到所有源的数据都可用为止。
2
Wait for the data to be committed for event testing - Large portions of existing testing frameworks do not have the ability to wait for multiple asynchronous events.
等待数据提交以进行事件测试——大部分现有测试框架没有能力等候多个异步事件。
3
If you use this approach a process could experience a situation where multiple receive activities wait for the same port type and operation.