Is there an existing issue for this?

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

Use case

Plugin developpers might need to configure the behaviors of their channel buffers. This is also needed to implement a solution for #125975.

Channel buffer documentation explains how to resize a channel buffer and how to configure the visibility of the error message related to overflow. This feature is implemented with a dedicated control channel that accepts two messages named 'resize' and 'overflow'.
For reference see:
https://github.com/flutter/engine/blob/93e8901490e78c7ba7e319cce4470d9c6478c6dc/lib/ui/channel_buffers.dart#L302-L309

The engine provides a way to call the 'resize' command on Android and iOS, but not on other platforms.
There is no utility method implemented to call the 'overflow' command.

Proposal

Provide helper functions to easily invoke the 'resize' and 'overflow' command on the control channel for all platforms.