https://github.com/cbsheng/cbsheng.github.io/blob/25ad06009201efb9b6ab1543dff860934a38329b/posts/golang%E6%A0%87%E5%87%86%E5%BA%93sync.pool%E5%8E%9F%E7%90%86%E5%8F%8A%E6%BA%90%E7%A0%81%E7%AE%80%E6%9E%90/index.html#L354 set 方法好像写了两次。
