restfulie client currently assumes that both request and response contains the same mime type

The request method expects that the response is of the same media type as the request, while it could be something different:

def request!(method, path, *args)
  representation = do_conneg_and_choose_representation(method, path, *args)
  return super(method, path, *args) unless representation
  if has_payload?(method, path, *args)
    payload = get_payload(method, path, *args)
    payload = representation.marshal(payload)
    args = set_marshalled_payload(method, path, payload, *args)
  end
  args = add_representation_headers(method, path, representation, *args)
  response = super(method, path, *args)
  if @raw
    response 
  else
    unmarshalled = representation.unmarshal(response.body)
    unmarshalled.extend(ResponseHolder)
    unmarshalled.response = response
    unmarshalled
  end
end