The developer of the buttons_tabbar flutter package written in the article Flutter: TabBar With Buttons as Tabs, he created the package is to create tab bar which common in iOS application, but he was unable to find one in the default flutter implementation.
A picture is worth a thousand words:-
After I implemented the example, I found an article 5 Ways of styling Tab in Flutter. I think we might able to style the default tabs to achieve similar effect.
Hence, before you use the buttons_tabbar flutter package in your application, I think you might first try to use the default tab and change its style to fit your application requirements.
If you are interested to reuse the source code of the screen, please check out the tab_buttons branch of the git repository hosted at https://github.com/limcheekin/fluwix. Feel free to fork the repository and send me pull request.
I'd love to hear from you whether the project is helpful to you. :)