perf: defer Queue creation in DedicatedThreadExecutor

[TimothyMakkison]

Defer initialisation of Queue in DedicatedThreadExecutor

I tried this with List<Task> _taskQueue and didn't see an improvement, presumably it will always contain at least one object so deferring is useless.

Before

After

[thomhurst]

Summary

Defers Queue allocation in DedicatedThreadSynchronizationContext to reduce memory allocations when the work queue is never used.

Critical Issues

None found ✅

Suggestions

None - this is a solid performance optimization that aligns with TUnit's "Performance First" principle. The lazy initialization pattern is correctly implemented with proper null checks and thread-safe initialization under the existing lock.

Verdict

✅ APPROVE - No critical issues

The change demonstrates:

• Reduced allocations in hot path (aligns with CRITICAL RULE And assertion conditions #4)
• Thread-safe lazy initialization
• Proper null handling in ProcessPendingWork
• Measurable performance improvement shown in benchmarks

[TimothyMakkison]

Is the modular pipelines check broken? #4508 is also failing because of a weak refernce check failiure in NET framework

[thomhurst]

Is the modular pipelines check broken? #4508 is also failing because of a weak refernce check failiure in NET framework

I think it's a flaky test that I need to look into