Greptile Summary

This PR addresses performance and correctness issues in projectile tracking hot paths. It fixes a critical bug where the Killed flag wasn't being set on ProjectileStruct due to value-type semantics in the ForEach lambda, replaces expensive LINQ operations with manual loops for better performance under load, and standardizes timestamp handling with DateTime.UtcNow.

Key Changes:

• Fixed struct mutation bug in HandleProjectileKill where Killed flag wasn't persisting (GetDataHandlers.cs:3303-3311)
• Added missing lock around RecentlyCreatedProjectiles in projectile update handler (TShock.cs:1840)
• Replaced LINQ .Any() with manual loops to reduce allocations in hot paths
• Moved threshold calculation outside loop in OnSecondUpdate (Bouncer.cs:3065)
• Switched all timestamp operations from DateTime.Now to DateTime.UtcNow for consistency

The changes preserve existing behavior while making projectile tracking more correct and efficient during packet-heavy combat scenarios.

Confidence Score: 5/5

• This PR is safe to merge with no concerns
• All changes are well-reasoned performance optimizations and correctness fixes. The critical struct mutation bug fix is correct, LINQ-to-loop conversions are logically equivalent, locking improvements enhance thread safety, and UTC timestamp usage improves consistency. No new issues introduced.
• No files require special attention

Important Files Changed

_{Last reviewed commit: 1f6705f}