Is there a way to mock flutter module API calls in native mobile application

Question

I have a native android application with flutter module integrated in it. I want to mock flutter module API calls but getting below error in Charles proxy

I am able to intercept native android API calls and modify the responses using charles but for flutter module code its not working. To debug flutter module code I am running below command in flutter codebase and I am also able to open dart dev tools and check API calls under network tab. But looks like it does not allow you modify responses.

flutter attach

Is there a simple way to mock API responses in such scenario? Do I have to update charles setting?How its working for native android API calls and not for flutter module calls