Feature request: measure bytes trasferred for a request and corresponding response

[eEQK]

I'm currently integrating Dio interceptor with Firebase Analitycs. I wanted to include the information about request+response size in the event, but I'm pretty sure it's not supported.

I'll be using a workaround for now, which is computing a sum of request body and response body, but that's not accurate.

Would it be possible to add it such information, perhaps to Response class?