code: protected function write(Response $response, $body): Response
      {
          $response->getBody()->write((string) $body);
          return $response;
      }
docs: Cleanly writes the body to the response.
  
  @param \Psr\Http\Message\ResponseInterface $response  The HTTP response
  @param mixed $body  The body to write
  @return \Psr\Http\Message\ResponseInterface  The same or new response