Issue in Flutter web: "Unsupported operation: Platform._operatingSystem"

[SebastienBtr]

• I have read the README
• I have already searched for the same problem
• I have read and done the setup for Android: IMPORTANT Note for Android and iOS and IMPORTANT Note for Android
• I have read and done the setup for iOS: IMPORTANT Note for Android and iOS and IMPORTANT Note for iOS
• I have ran the sample app and it does not work there

Environment

Technology	Version
Flutter version	1.21.0-9.1.pre
Plugin version	^4.0.0+4
Android version
iOS version
Xcode version

Device information:

Ussing flutter run -d chrome

Description

Expected behavior:

The plugin should work on web

Current behavior:

An exception is thrown: Unsupported operation: Platform._operatingSystem

See the related flutter issue: flutter/flutter#36126

Steps to reproduce

1. Add inAppWebView in a statefull widget
2. Run with: flutter run -d chrome
3. See exception

[pichillilorenzo]

The fix about this error will be available in the next version 5.0.0. However, flutter_inappwebview doesn't support Flutter Web, so it will not work on the Web.