This allows the thread to stop waiting if no messages have arrived, and checka flag to see if we should keep waiting for messages.
这将允许线程在没有消息到达的情况下停止等待，查看标志，看看是否应该坚持等待消息。
2
She saw that the Chili's in Evanston was not on her schedule for the day, but she could stop by to check the situation at a later point in the day when she would be nearby.
As the accident goes from a spill to something far worse, it may be BP paying the check, but ultimately the buck will stop in the White House, and Obama will be judged.