这么做是为了处理线程池中的死锁，当太多线程等待其他任务结束时就会出现死锁。
This was done to address deadlocks in the thread-pool. These deadlocks were caused when too many threads were waiting on other tasks.
我们的主线程一直等待输入任务单元结束时产生的事件信号。
Our main thread waits on an event that is signaled when input is dying.
而获取事件的线程并不等待处理线程的结束。
The thread responsible for fetching the event does not wait for the end of the processing thread.
设置等待关联进程退出的时间，并在该段时间结束前或该进程退出前，阻止当前线程执行。
Sets the period of time to wait for the associated process to exit, and blocks the current thread of execution until the time has elapsed or the process has exited.
设置等待关联进程退出的时间，并在该段时间结束前或该进程退出前，阻止当前线程执行。
Sets the period of time to wait for the associated process to exit, and blocks the current thread of execution until the time has elapsed or the process has exited.
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