[manuelmayer-dev]

Closes #

Summary

• Assert the native-link queue against its fixed capacity.
• Avoid a timing-sensitive comparison while stream pumps are still enqueueing reserved frames.

Testing

• git diff --check
• GitHub CI (local SDK 10.0.400 unavailable)

Checklist

• Tests were updated where needed
• No documented behavior or public contract changed
• I reviewed and understand every submitted change