Psr7Middlewares\Middleware\Payload::__invoke PHP Method

    public function __invoke(ServerRequestInterface $request, ResponseInterface $response, callable $next)
    {
        if (!$request->getParsedBody() && in_array($request->getMethod(), ['POST', 'PUT', 'PATCH', 'DELETE', 'COPY', 'LOCK', 'UNLOCK'], true)) {
            $resolver = $this->resolver ?: new Transformers\BodyParser($this->options);
            $transformer = $resolver->resolve(trim($request->getHeaderLine('Content-Type')));
            if ($transformer) {
                try {
                    $request = $request->withParsedBody($transformer($request->getBody()));
                } catch (\Exception $exception) {
                    return $response->withStatus(400);
                }
            }
        }
        return $next($request, $response);
    }