title: Flutter: Warning: Operand of null-aware operation '!' has type 'WidgetsBinding' which excludes null
body: <p>Recently, my Debug Console was showing something that wasn't showing before. This happens when I use package <a href="https://pub.dev/packages/flutter_typeahead" rel="nofollow noreferrer"><code>flutter_typeahead</code></a>. I don't know if this is an error or a warning. Below is my Debug Console:</p>
  <pre><code>Launching lib\main.dart on Chrome in debug mode...
  : Warning: Operand of null-aware operation '!' has type 'WidgetsBinding' which excludes null.
  - 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('../../../Documents/flutter/packages/flutter/lib/src/widgets/binding.dart').
      WidgetsBinding.instance!.removeObserver(this);
                     ^
  
  : Warning: Operand of null-aware operation '!' has type 'WidgetsBinding' which excludes null.
  - 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('../../../Documents/flutter/packages/flutter/lib/src/widgets/binding.dart').
      WidgetsBinding.instance!.addObserver(this);
                     ^
  : Warning: Operand of null-aware operation '!' has type 'WidgetsBinding' which excludes null.
  - 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('../../../Documents/flutter/packages/flutter/lib/src/widgets/binding.dart').
      WidgetsBinding.instance!.addPostFrameCallback((duration) {
                     ^
  : Warning: Operand of null-aware operation '!' has type 'WidgetsBinding' which excludes null.
  - 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('../../../Documents/flutter/packages/flutter/lib/src/widgets/binding.dart').
      WidgetsBinding.instance!.removeObserver(this);
                     ^
  
  : Warning: Operand of null-aware operation '!' has type 'WidgetsBinding' which excludes null.
  - 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('../../../Documents/flutter/packages/flutter/lib/src/widgets/binding.dart').
      WidgetsBinding.instance!.addObserver(this);
                     ^
  
  : Warning: Operand of null-aware operation '!' has type 'WidgetsBinding' which excludes null.
  - 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('../../../Documents/flutter/packages/flutter/lib/src/widgets/binding.dart').
      WidgetsBinding.instance!.addPostFrameCallback((duration) {
                     ^
  This app is linked to the debug service: ws://127.0.0.1:60355/d-7F-zZtGz0%3D/ws
  Debug service listening on ws://127.0.0.1:60355/d-7F-zZtGz0=/ws
   Running with sound null safety
  Connecting to VM Service at ws://127.0.0.1:60355/d-7F-zZtGz0=/ws
  </code></pre>
  <p>Appreciate if someone can advise. Thank you in advance!</p>