Make UnalignedSlice Send and Sync.

[Mark Hildebrand (hildebrandmw)]

Needed for the inmem2 quantization work.

[Copilot]

Pull request overview

This PR makes diskann-vector::UnalignedSlice explicitly Send and Sync (with T: Sync bounds), enabling it to be moved/shared across threads for upcoming in-memory quantization work.

Changes:

• Add unsafe impl Send for UnalignedSlice<'_, T> where T: Sync.
• Add unsafe impl Sync for UnalignedSlice<'_, T> where T: Sync.

Suppressed comments (1)

diskann-vector/src/unaligned.rs:31

• The SAFETY comment for the Sync impl currently refers to "&T is send"; for Sync it’s clearer to justify the bound directly as T: Sync (equivalently, &T: Send). This helps avoid confusion between the Send and Sync auto-traits.

/// SAFETY: `UnalignedSlice` is like a `&[T]`: it can be shared with other threads when `&T`
/// is send, implying the bound `T: Sync`.
unsafe impl<T> Sync for UnalignedSlice<'_, T> where T: Sync {}

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.

[Codecov Comments Bot (codecov-commenter)]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.55%. Comparing base (860cf47) to head (3a74727).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1348      +/-   ##
==========================================
- Coverage   91.55%   91.55%   -0.01%     
==========================================
  Files         521      521              
  Lines      100347   100347              
==========================================
- Hits        91877    91874       -3     
- Misses       8470     8473       +3     

Flag	Coverage Δ
miri	91.55% <ø> (-0.01%)	⬇️
unittests	91.23% <ø> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
diskann-vector/src/unaligned.rs	90.90% <ø> (ø)

... and 3 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.