fix: use Buffer.alloc() with snappy-wasm

[twoeths]

Motivation

• high MarkSweepCompact gc on feat: use snappy-wasm (#6483) #8647
• the reason is the use of Buffer.allocUnsafe() as found in feat: use different snappy implementations for different topics #8670 (comment)
• an alternative to feat: use different snappy implementations for different topics #8670

Description

• use @chainsafe/snappy-wasm for all topics but with Buffer.alloc()
• this is deployed to feat2

[gemini-code-assist]

Summary of Changes

Hello @twoeths, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses a critical performance issue related to excessive garbage collection by modifying how memory buffers are allocated within the snappy-wasm compression and decompression logic. By transitioning from Buffer.allocUnsafe() to Buffer.alloc(), the change ensures that newly allocated memory is zero-filled, which helps prevent potential memory-related bugs and significantly reduces GC pressure. This adjustment is expected to improve the overall stability and performance of the system by optimizing memory management during data transformation.

Highlights

• GC Performance Improvement: Replaced Buffer.allocUnsafe() with Buffer.alloc() in the DataTransformSnappy class to mitigate high MarkSweepCompact garbage collection activity observed on the main thread of nodes, specifically addressing issues similar to feat: use snappy-wasm (#6483) #8647.

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[gemini-code-assist]

Code Review

This pull request addresses a performance issue related to garbage collection by replacing Buffer.allocUnsafe() with Buffer.alloc() when handling snappy compression and decompression. The changes are correct and effectively resolve the reported problem. My review includes suggestions to improve the new code comments for better clarity and long-term maintainability, and also points out an additional security benefit of the change in one of the cases.

[twoeths]

this fixes the issue specified on PR-8647

• attestation job times are the same to unstable

• also the memory on main thread + network thread

[twoeths]

there is not clear differences between metrics of this PR vs #8670
except for Event loop lag NETWORK WORKER of this PR on hoodi sas node

set_immediate is way smaller than this metric of #8670 (feat3)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 52.03%. Comparing base (a6b3c51) to head (7fc5ed0).
⚠️ Report is 1 commits behind head on cayman/snappy.

Additional details and impacted files

@@              Coverage Diff               @@
##           cayman/snappy    #8671   +/-   ##
==============================================
  Coverage          52.03%   52.03%           
==============================================
  Files                848      848           
  Lines              65809    65809           
  Branches            4809     4809           
==============================================
  Hits               34241    34241           
  Misses             31499    31499           
  Partials              69       69           

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