The app is compiled with the dart2js compiler for
best performance.

The command flutter run --release compiles to release mode.
Your IDE supports this mode. Android Studio, for example,
provides a Run > Run… menu option, as well as a triangular
green run button icon on the project page.
You can compile to release mode for a specific target
with flutter build <target>. For a list of supported targets,
use flutter help build.

For more information, see the docs on releasing
iOS and Android apps.

Profile

In profile mode, some debugging ability is maintained—enough
to profile your app’s performance. Profile mode is disabled on
the emulator and simulator, because their behavior is not representative
of real performance. On mobile, profile mode is similar to release mode,
with the following differences:

Some service extensions, such as the one that enables the performance
overlay, are enabled.