How can I do login with OAuth2 (Identity Server 4) using flutter web?

I have been trying to do Oauth2 login of Identity Server 4 using flutter, I have successfully implemented the login on iPad using: https://pub.dev/packages/flutter_web_auth library but as this library says it also supports web but seems like it is not working on the flutter web app, can you guys kindly suggest how can I make the web app work with Oauth2 or is there any other way to make the OAuth2 login work with flutter web?

I need to do this ASAP, so any help will be really appreciated.