We use a _ placeholder shortcut again in another function literal that we pass to foreach .
我们在传给foreach的这个字面函数中再一次使用了一个_占位符。
This time it is outside of the foreach loop , because we clearly only need one !
这次它在foreach循环之外，因为我们只需要一个！
The problem gets worse when you consider that the foreach method might want to call the lambda from other threads , so that the function could be applied to different elements of the collection in parallel .
