Use case

I wanted to create this Design:

But when I use ExpansionTile this is happening:

There're borders on top and bottom.

After I had a look into the ExpansionTile widget, I saw that these borders cannot be controlled outside of the ExpansionTile:

It's only an internal variable, but I want to control the border to disappear, when the ExpansionTile is expanded.

Proposal

It would be great if there would a decoration or border argument to pass into the ExpansionTile