We've seen some internal code where making it inline (ie, as a value type) improved perf as it decreased working set.

我们看到过很多内部代码，使用值类型来提高性能，同时减小工作集大小。

youdao

Since all of our built-in collection types implement this interface there are no perf gains in the most common scenarios.

自从我们所有的内建集合类型实现了此接口以后，在那些最常见场景下并未获得任何性能收益。

youdao

Initially we thought that adding this type would allow code to gain better perf in scenarios where you just want to get the count and then do some interesting stuff with it.

起初我们认为，添加这个类型将使得代码在某些场景(你只想获得计数，然后对它做一些有趣的东西)下获得更好的性能。

youdao