Add padding around class WindowWrap to improve count request performance

Issue Description
Type: enhancement

Describe what happened (or what feature you want)
Because counting request is a high concurrency scenario, add padding around class `WindowWrap` can solve false sharing problem to improve the performance.

Locate the Java class WindowWrap and trace how it is used by the high-concurrency counting request path. Review the project's existing performance tests or benchmarks, then verify that padding is applied around WindowWrap and that the counting scenario shows improved false-sharing behavior without regressions.

Written by the indexing model from the issue text.