warning GBC99161D in windows build

"warning GBC99161D: Operand of null-aware operation '!' has type 'WidgetsBinding' which excludes null. "
in flutter build windows
lines:

flow_builder-0.0.6/lib/flow_builder.dart(367,27)
flow_builder-0.0.6/lib/flow_builder.dart(372,29)

-----

I did remove de two "!" and warnings disapeared.

[√] Flutter (Channel master, 2.11.0-0.0.pre.448, on Microsoft Windows [versão 10.0.19043.1466], locale pt-BR)
• Flutter version 2.11.0-0.0.pre.448 at C:\tools\flutter
• Upstream repository https://github.com/flutter/flutter.git
• Framework revision 283e48bde4 (2 days ago), 2022-02-04 23:00:18 -0500
• Engine revision bbe4e9758c
• Dart version 2.17.0 (build 2.17.0-85.0.dev)
• DevTools version 2.10.0

[√] Android toolchain - develop for Android devices (Android SDK version 30.0.0-rc1)
• Android SDK at C:\Users\Dario\AppData\Local\Android\sdk
• Platform android-32, build-tools 30.0.0-rc1
• Java binary at: C:\Program Files\Android\Android Studio1\jre\bin\java
• Java version OpenJDK Runtime Environment (build 11.0.11+9-b60-7590822)
• All Android licenses accepted.

[√] Chrome - develop for the web
• Chrome at C:\Program Files (x86)\Google\Chrome\Application\chrome.exe

[√] Visual Studio - develop for Windows (Visual Studio Community 2019 16.11.7)
• Visual Studio at C:\Program Files (x86)\Microsoft Visual Studio\2019\Community
• Visual Studio Community 2019 version 16.11.31911.196
• Windows 10 SDK version 10.0.19041.0

[√] Android Studio (version 2021.1)
• Android Studio at C:\Program Files\Android\Android Studio1
• Flutter plugin can be installed from:
https://plugins.jetbrains.com/plugin/9212-flutter
• Dart plugin can be installed from:
https://plugins.jetbrains.com/plugin/6351-dart
• Java version OpenJDK Runtime Environment (build 11.0.11+9-b60-7590822)

[!] Android Studio (version 4.1)
• Android Studio at C:\Program Files\Android\Android Studio
• Flutter plugin can be installed from:
https://plugins.jetbrains.com/plugin/9212-flutter
• Dart plugin can be installed from:
https://plugins.jetbrains.com/plugin/6351-dart
X Unable to determine bundled Java version.
• Try updating or re-installing Android Studio.

[√] VS Code (version 1.64.0)
• VS Code at C:\Users\Dario\AppData\Local\Programs\Microsoft VS Code
• Flutter extension version 3.35.20220201

[√] Connected device (3 available)
• Windows (desktop) • windows • windows-x64 • Microsoft Windows [versão 10.0.19043.1466]
• Chrome (web) • chrome • web-javascript • Google Chrome 97.0.4692.99
• Edge (web) • edge • web-javascript • Microsoft Edge 98.0.1108.43