code: func (a *Core) post(uri string, reqBody, response interface{}) (*http.Response, error) {
  	content, err := json.Marshal(reqBody)
  	if err != nil {
  		return nil, errors.New("failed to marshal message")
  	}
  
  	return a.retrievablePost(uri, content, response)
  }
docs: // post performs an HTTP POST request and parses the response body as JSON,
  // into the provided respBody object.