StatisticSlot中fireEntry操作和本次统计node.addPassRequest非原子问题

## Issue Description
从代码中看到，StatisticSlot中fireEntry操作和本次统计node.addPassRequest并非原子操作，请问在并发较大的情况下如何保证通过qps的准确性的呢

Type: *bug report* or *feature request*

### Describe what happened (or what feature you want)

### Describe what you expected to happen

### How to reproduce it (as minimally and precisely as possible)

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### Tell us your environment

### Anything else we need to know?

Start by tracing StatisticSlot.fireEntry alongside node.addPassRequest and reviewing the concurrency assumptions around the QPS calculation. Define a reproducible high-concurrency case and compare the observed and expected pass counts; done requires an agreed resolution and regression coverage if a code change is selected.

Written by the indexing model from the issue text.