How to create an AppBar with a bottom coloured border in Flutter?

Question

I would like to create an App Bar like this which has a bottom border as well a tint of shadow which can be done using elevation. Could someone provide a sample code snippet to achieve this

Answer 1

Maybe something like this

AppBar(
   bottom: PreferredSize(
     preferredSize: const Size.fromHeight(4.0),
     child: Container(
        color: Colors.orange,
        height: 4.0,
     )),
   )