Performance test catching up BN's at high TPS (entire block buffer)

### Background

A test to do is check how the BN handles potentially streaming dozens of blocks that are large. e.g. at 10K TPS, if all those blocks are buffered and then we suddenly get a connection to a BN, can the BN handle a large volume of traffic across multiple blocks/requests in a very short time.

### Acceptance Criteria

TBD

### Dependencies

_No response_

### Definition of Ready (DoR) Checklist

- [ ] Clear acceptance criteria
- [ ] Clear and detailed description
- [ ] Dependencies identified
- [ ] Links to documentation
- [ ] Should be completable in 2-3 Days
- [ ] Initial draft of Low-level design document
- [ ] At least high level test plan
- [ ] Groomed/Estimated

### Definition of Done (DoD) Checklist

- [ ] Acceptance Criteria complete
- [ ] No Codacy issues greater than minor (in new code)
- [ ] JavaDocs updated/created
- [ ] Code commented
- [ ] Unit tests created/updated
- [ ] 80% test code coverage (in new code)
- [ ] Happy Path and major negative cases in HAPI tests as applicable

No files, tests, or entry points are named. Start by locating the BN block-buffering code and existing performance-test harness, then establish a test plan for dozens of large blocks at 10K TPS and a burst of multi-block requests. Done requires agreed acceptance criteria and evidence that the BN handles the defined traffic volume.

Written by the indexing model from the issue text.