code: func (r *Request) Body(in interface{}) *Request {
  	b := new(bytes.Buffer)
  	if err := json.NewEncoder(b).Encode(&in); err != nil {
  		r.err = err
  		return r
  	}
  	r.body = b
  	return r
  }
docs: // Body pass in a body to set, this is for POST, PUT
  // and PATCH requests