text: Title: [Feature] Add body to response.request
  Body: **Is your feature request related to a problem? Please describe.**
  Just a compatibility problem with the existing requests package in Python.  If we POST a request then the response has a request object as an attribute and being a POST, that request object has a body attribute (being the posted data). I love this package, thanks enormously! This would help it slot in as a simple replacement for request, but may of course be one of many compatibility issues in the end. Just one I found when I swapped to this package in an existing script that POSTs and checks response.request.body.
  
  **Describe the solution you'd like**
  That the request recorded against a response contain all the request attributes ...
  
  **Describe alternatives you've considered**
  I just take it from the request I sent ;-)