code: private function debugRequest($url, array $headers, $body)
      {
          $str = $url.PHP_EOL;
  
          $str .= array_reduce(array_keys($headers), function ($str, $key) use ($headers) {
              $str .= $key.': '.$headers[$key].PHP_EOL;
              return $str;
          }, '');
  
          $str .= $body;
  
          $this->debug($str);
      }
docs: Sends a debug string of the request details.
  
  @param string $url API endpoint.
  @param array $headers Associative array of HTTP headers.
  @param string $body The JSON body of the request.