For testing use Physical Device because it close to real life scenario.
DevTools is a suite of pre-packaged Application Performance Monitoring and Debugging tools that is available in Dart & Flutter.
X-ray vision for Flutter apps, spotting bugs and boosting performance like a debugging superhero.
→ List Of DevTools
Credit: @ashitaprasad
→ Additional Check on debug mode
→ Runs on AOT instead of JIT
→ Close to actual release
Mastering Dart & Flutter DevTools — Series Introduction & Installation [Part 1 of 8]
→ 80% of users delete apps because of Performance Issues.
→ CPU Profiler View provides insights into the CPU usage of an app.