Warning: Operand of null-aware operation '!.' has type 'SchedulerBinding' which excludes null.

[ValentinVignal]

Describe the bug

When running the tests, I get the warning:

../../../.pub-cache/hosted/pub.dartlang.org/performance-0.1.0+1/lib/src/overlay.dart:223:22: Warning: Operand of null-aware operation '!' has type 'SchedulerBinding' which excludes null.
 - 'SchedulerBinding' is from 'package:flutter/src/scheduler/binding.dart' ('../flutter/packages/flutter/lib/src/scheduler/binding.dart').
    SchedulerBinding.instance!.addTimingsCallback(_timingsCallback);
                     ^
../../../.pub-cache/hosted/pub.dartlang.org/performance-0.1.0+1/lib/src/overlay.dart:228:22: Warning: Operand of null-aware operation '!' has type 'SchedulerBinding' which excludes null.
 - 'SchedulerBinding' is from 'package:flutter/src/scheduler/binding.dart' ('../flutter/packages/flutter/lib/src/scheduler/binding.dart').
    SchedulerBinding.instance!.removeTimingsCallback(_timingsCallback);
                     ^
../../../.pub-cache/hosted/pub.dartlang.org/performance-0.1.0+1/lib/src/overlay.dart:251:22: Warning: Operand of null-aware operation '!' has type 'SchedulerBinding' which excludes null.
 - 'SchedulerBinding' is from 'package:flutter/src/scheduler/binding.dart' ('../flutter/packages/flutter/lib/src/scheduler/binding.dart').
    SchedulerBinding.instance!.addPostFrameCallback((timeStamp) {

To Reproduce

I'm using flutter 3.0.5.

Run flutter test on :

// ignore: unused_import
import 'package:performance/performance';
import 'package:flutter_test/flutter_test.dart';

void main() {
  testWidgets('Counter increments smoke test', (WidgetTester tester) async {});
}

Expected behavior

There should not be any compilation error