<?phpnamespace GuzzleHttp;use Psr\Http\Message\RequestInterface;use Psr\Http\Message\ResponseInterface;use Psr\Http\Message\UriInterface;/** * Represents data at the point after it was transferred either successfully * or after a network error. */final class TransferStats{    /**     * @var RequestInterface     */    private $request;    /**     * @var ResponseInterface|null     */    private $response;    /**     * @var float|null     */    private $transferTime;    /**     * @var array     */    private $handlerStats;    /**     * @var mixed|null     */    private $handlerErrorData;    /**     * @param RequestInterface       $request          Request that was sent.     * @param ResponseInterface|null $response         Response received (if any)     * @param float|null             $transferTime     Total handler transfer time.     * @param mixed                  $handlerErrorData Handler error data.     * @param array                  $handlerStats     Handler specific stats.     */    public function __construct(        RequestInterface $request,        ?ResponseInterface $response = null,        ?float $transferTime = null,        $handlerErrorData = null,        array $handlerStats = []    ) {        $this->request = $request;        $this->response = $response;        $this->transferTime = $transferTime;        $this->handlerErrorData = $handlerErrorData;        $this->handlerStats = $handlerStats;    }    public function getRequest(): RequestInterface    {        return $this->request;    }    /**     * Returns the response that was received (if any).     */    public function getResponse(): ?ResponseInterface    {        return $this->response;    }    /**     * Returns true if a response was received.     */    public function hasResponse(): bool    {        return $this->response !== null;    }    /**     * Gets handler specific error data.     *     * This might be an exception, a integer representing an error code, or     * anything else. Relying on this value assumes that you know what handler     * you are using.     *     * @return mixed     */    public function getHandlerErrorData()    {        return $this->handlerErrorData;    }    /**     * Get the effective URI the request was sent to.     */    public function getEffectiveUri(): UriInterface    {        return $this->request->getUri();    }    /**     * Get the estimated time the request was being transferred by the handler.     *     * @return float|null Time in seconds.     */    public function getTransferTime(): ?float    {        return $this->transferTime;    }    /**     * Gets an array of all of the handler specific transfer data.     */    public function getHandlerStats(): array    {        return $this->handlerStats;    }    /**     * Get a specific handler statistic from the handler by name.     *     * @param string $stat Handler specific transfer stat to retrieve.     *     * @return mixed|null     */    public function getHandlerStat(string $stat)    {        return $this->handlerStats[$stat] ?? null;    }}