Is there an existing issue for this?

• I have searched the existing issues
• I have read the guide to filing a bug

Use case

The default ExpansionTile animation looks glitchy because the speeds in which the tile expands and collapses are different.

I will post 3 videos comparing the default one, one with a linear curve and another one with a linear curve and a little longer duration so what I mean is more clear.

Default ExpansionTile animation

ExpansionTile with linear curve

ExpansionTile with linear curve and a little longer animation (a little bit smoother)

Proposal

The proposed fix is simply to expose parameters to let us control the curve and duration of the expansion animation.