1. Write a test that scrolls through a list of items

In this recipe, record the performance of an app as it scrolls through a
list of items. To focus on performance profiling, this recipe builds
on the Scrolling recipe in widget tests.

Follow the instructions in that recipe to create an app and write a test to
verify that everything works as expected.

2. Record the performance of the app

Next, record the performance of the app as it scrolls through the
list. Perform this task using the traceAction()
method provided by the IntegrationTestWidgetsFlutterBinding class.

This method runs the provided function and records a Timeline
with detailed information about the performance of the app. This example
provides a function that scrolls through the list of items,
ensuring that a specific item is displayed. When the function completes,
the traceAction() creates a report data Map that contains the Timeline.

3. Save the results to disk