Is there an existing issue for this?

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

Use case

Hi. There is a fallback font option in TextStyle.
https://api.flutter.dev/flutter/painting/TextStyle/fontFamilyFallback.html

But there is no ability to pass it to the Icon widget.

This makes impossible to specify fallback font for icons.

Let me give you an example.

Imagine that you need to have an ability to swap icons from downloadable font.
It would be great to specify fallback font to be from design system package.

The flow is simple

• download custom font(i may want to serve font with only one icon substituted)
• use this font name as default for icon retrieval
• specify a fallback frot from design system package.

Proposal

Add fallback font to IconData class