[Tcode-Motion]

💡 What: Pre-calculated String buffer capacity using String::with_capacity and replaced write! macro with push_str for string and boolean arguments in fstring_concat.

🎯 Why: fstring_concat previously created an empty String with String::new() and appended each formatted argument using write!(res, "{}", arg). This caused multiple heap re-allocations and unnecessary write! format macro overhead during string concatenation loops.

📊 Measured Improvement: Execution time for 100,000 runs of fstring_concat decreased from ~166.0ms to ~131.5ms, representing a ~20.7% speedup in debug execution time.

---

PR created automatically by Jules for task 18209321494506362091 started by @Tcode-Motion

[google-labs-jules]

👋 Jules, reporting for duty! I'm here to lend a hand with this pull request.

When you start a review, I'll add a 👀 emoji to each comment to let you know I've read it. I'll focus on feedback directed at me and will do my best to stay out of conversations between you and other bots or reviewers to keep the noise down.

I'll push a commit with your requested changes shortly after. Please note there might be a delay between these steps, but rest assured I'm on the job!

For more direct control, you can switch me to Reactive Mode. When this mode is on, I will only act on comments where you specifically mention me with @jules. You can find this option in the Pull Request section of your global Jules UI settings. You can always switch back!

New to Jules? Learn more at jules.google/docs.

---

For security, I will only act on instructions from the user who triggered this task.