chore: use Byte instead of Vec<u8> in some channels

[LesnyRumcajs]

Summary of changes

This saves some allocation cloning

When a value is sent, all Receiver handles are notified and will receive the value. The value is stored once inside the channel and cloned on demand for each receiver. Once all receivers have received a clone of the value, the value is released from the channel.

See https://docs.rs/tokio/latest/tokio/sync/broadcast/index.html

Bytes's clone is a shallow clone so it would just increment a counter

Reference issue to close (if applicable)

Closes

Other information and links

Change checklist

• I have performed a self-review of my own code,
• I have made corresponding changes to the documentation. All new code adheres to the team's documentation standards,
• I have added tests that prove my fix is effective or that my feature works (if possible),
• I have made sure the CHANGELOG is up-to-date. All user-facing changes should be reflected in this document.

Outside contributions

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• I have read and agree to the AI Policy document. I understand that failure to comply with the guidelines will lead to rejection of the pull request.

Summary by CodeRabbit

• Refactor
  • Updated internal data type representations in write operations handling across storage components for improved efficiency and consistency.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: 1973c893-886a-41e0-a80c-365958741e43

📥 Commits

Reviewing files that changed from the base of the PR and between 7d1062a and 475b3e9.

📒 Files selected for processing (5)

• src/db/car/many.rs
• src/db/gc/snapshot.rs
• src/db/mod.rs
• src/db/parity_db.rs
• src/db/parity_db/gc.rs

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Walkthrough

The changes update the broadcast payload type for blockstore write operations subscriptions from Vec<(Cid, Vec<u8>)> to Vec<(Cid, bytes::Bytes)> across the trait definition and all implementations.

Changes

Cohort / File(s)	Summary
Trait and Wrapper Implementations src/db/mod.rs, src/db/car/many.rs, src/db/parity_db/gc.rs	Updated BlockstoreWriteOpsSubscribable::subscribe_write_ops return type from Receiver<Vec<(Cid, Vec<u8>)>> to Receiver<Vec<(Cid, bytes::Bytes)>> across trait definition and delegating implementations.
ParityDb Implementation src/db/parity_db.rs	Updated subscribe_write_ops return type and modified put_keyed and put_many_keyed paths to construct bytes::Bytes payloads using Bytes::copy_from_slice for subscriber notifications; tests updated to assert new payload types.
Snapshot Garbage Collector src/db/gc/snapshot.rs	Changed SnapshotGarbageCollector::memory_db field type from RwLock<Option<HashMap<Cid, Vec<u8>>>> to RwLock<Option<HashMap<Cid, bytes::Bytes>>> for export staging store.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 14.29% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main change: replacing Vec with Bytes in broadcast channels across multiple files to reduce allocation overhead.

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🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch bytes-in-channels

✨ Simplify code

• Create PR with simplified code
• Commit simplified code in branch bytes-in-channels

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[codecov]

Codecov Report

❌ Patch coverage is 62.50000% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 63.96%. Comparing base (c934f0f) to head (475b3e9).
⚠️ Report is 3 commits behind head on main.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/db/car/many.rs	0.00%	1 Missing ⚠️
src/db/parity_db.rs	83.33%	1 Missing ⚠️
src/db/parity_db/gc.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

Files with missing lines	Coverage Δ
src/db/gc/snapshot.rs	0.00% <ø> (ø)
src/db/mod.rs	37.25% <ø> (ø)
src/db/car/many.rs	62.08% <0.00%> (ø)
src/db/parity_db.rs	69.00% <83.33%> (-0.25%)	⬇️
src/db/parity_db/gc.rs	33.05% <0.00%> (ø)

... and 4 files with indirect coverage changes

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