Congratulations, you are now running Dart DevTools!

Note:
  This is not the only way to launch DevTools.
  If you are using IntelliJ,
  you can open DevTools by going to
  Flutter Inspector -> More Actions -> Open DevTools:

Set a breakpoint.
Now that you have DevTools running,
select the Debugger tab in the blue bar along the top.
The debugger pane appears and, in the lower left,
see a list of libraries used in the example.
Select lib/main.dart to display your Dart code
in the center pane.

Set a breakpoint.
In the Dart code,
scroll down to where progress is updated:

    
for (final controller in controllers) {
  if (controller.value.text.isNotEmpty) {
    progress += 1 / controllers.length;
  }
}