name : MessageFormatterInterface.php <?php namespace GuzzleHttp; use Psr\Http\Message\RequestInterface; use Psr\Http\Message\ResponseInterface; interface MessageFormatterInterface { /** * Returns a formatted message string. * * @param RequestInterface $request Request that was sent * @param ResponseInterface|null $response Response that was received * @param \Throwable|null $error Exception that was received */ public function format(RequestInterface $request, ?ResponseInterface $response = null, ?\Throwable $error = null): string; }