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 IconButton internally uses a MaterialStateController, however it is not possible for the user to provide one.

Since the other buttons do expose the option to provide our own MaterialStateControllers, I think for consistency (and also for a particular situation I am trying to solve), it would make sense to also expose this option for the IconButton.

Proposal

Give the user the option to provide the MaterialStateController