def get!(path, extra=nil, params={})
      path, extra, params = normalize path, extra, params
      key = cache_key path, extra, params

      @last_payload = cache.get key do
        http_get(path, extra, params)
      end

      @last_url = @last_payload.request.last_uri.to_s
      @last_payload
    end
def get!(path, extra=nil, params={})
      path, extra, params = normalize path, extra, params
      key = cache_key path, extra, params

      @last_payload = cache.get key do
        http_get(path, extra, params)
      end

      @last_url = @last_payload.request.last_uri.to_s
      @last_payload
    end
Make a request or get it from cache, and return the entire {Payload}
 object.