How to develop a Flutter package | Flutter Tutorial: Статья о том, как создать Flutter Package и опубликовать его.
http://www.sandromaglione.com/blog/2020/02/02/how-to-develop-a-flutter-package-flutter-tutorial/
http://www.sandromaglione.com/blog/2020/02/02/how-to-develop-a-flutter-package-flutter-tutorial/