Debug mode also executes code in a different way than release mode.
The debug build compiles the Dart code “just in time” (JIT) as the
app runs, but profile and release builds are pre-compiled to native
instructions (also called “ahead of time”, or AOT) before the app is
loaded onto the device. JIT can cause the app to pause for JIT
compilation, which itself can cause jank.

Run in profile mode

Flutter’s profile mode compiles and launches your application
almost identically to release mode, but with just enough additional
functionality to allow debugging performance problems.
For example, profile mode provides tracing information to the
profiling tools.

Note:
  DevTools can’t connect to a Flutter web app running
  in profile mode. Use Chrome DevTools to
  generate timeline events for a web app.

Launch the app in profile mode as follows: