Issue
I was trying to use custom Navigation bar and after using it I was getting this following error So I want to know why I am getting it , because the same thing was given in documentation itself.
Solution
I have to do some updating part since the version was not uptodate.
So I have updated the package and restart the application.
Answered By – Manishyadav
Answer Checked By – Jay B. (FlutterFixes Admin)