Improve MetaDb table pooling

[michaelstaib]

No description provided.

[Copilot]

Pull request overview

This PR improves MemorySegmentTablePool behavior for segment-table sizes that exceed the bucketed range by introducing a private fallback ArrayPool<MemorySegment>, enabling deterministic reuse of cleared tables and allowing downstream callers (MetaDb creation) to remove redundant clearing.

Changes:

• Introduces a private fallback pool for MemorySegment[] tables larger than the bucketed range, and routes rent/return through it.
• Updates tests to validate clearing behavior for the fallback path.
• Updates MemoryArena XML docs and removes now-redundant chunks.AsSpan().Clear() calls in Fusion MetaDb initialization.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/HotChocolate/Utilities/test/Utilities.Tests/MemorySegmentTablePoolTests.cs	Updates/extends pooling tests to cover fallback-table reuse + clearing semantics.
src/HotChocolate/Utilities/src/Utilities.Buffers/MemorySegmentTablePool.cs	Adds a private fallback ArrayPool and updates rent/return logic for out-of-range table sizes.
src/HotChocolate/Utilities/src/Utilities.Buffers/MemoryArena.cs	Updates RentSegmentTable documentation to reflect the cleared-table contract.
src/HotChocolate/Fusion/src/Fusion.Execution/Text/Json/SourceResultDocument.MetaDb.cs	Removes redundant clearing of chunk-slot tables now that they’re guaranteed cleared.
src/HotChocolate/Fusion/src/Fusion.Execution/Text/Json/CompositeResultDocument.MetaDb.cs	Removes redundant clearing of chunk-slot tables now that they’re guaranteed cleared.

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Patch coverage

100.0% of changed lines covered (8/8)

File	Covered	Changed	Patch %
…/Utilities/src/Utilities.Buffers/MemorySegmentTablePool.cs	8	8	100.0% 🟢

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Project coverage: 53.4% (227648/426407 lines)