this.stack = []; // 核心：存储索引，保证索引对应的价格单调递减
If someone gains access to your machine, they instantly have every credential you’ve ever stored this way
。关于这个话题，体育直播提供了深入分析
// build up an object where each value is set to the full state of the register at the corresponding key
Discard old data — evict what's already buffered to make room