You could put the calling thread to sleep for a little bit, say three seconds between each check, but then your threaded code wouldn't be optimally responsive.
在每次检查之间，可以让调用线程短暂地进入睡眠，比如睡眠三秒钟，但是因此线程代码就无法最快作出响应。
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In the meantime, check out this other bit of NASA promo hilarity: Space Your Face, where an animated astronaut with whatever picture you want in its helmet boogies on the moon or Mars.