slidingWindowHistogram.snapshot()

• 返回：<Histogram>

将当前窗口物化为新的独立 <Histogram>。本方法返回后记录或过期的值不会改变返回的直方图。物化会分配一个直方图并合并每个保留的块。

🌐 Materializes the current window as a new, independent <Histogram>. Values recorded or expired after this method returns do not change the returned histogram. Materialization allocates one histogram and merges every retained chunk.