isRegistration example

    /** * @param array<mixed> $options */
    public function __invoke(RequestInterface $request, array $options): PromiseInterface
    {
        if ($this->inner->count() > 0) {
            return \call_user_func($this->inner, $request, $options);
        }

        if ($this->isRegistration($request)) {
            $this->registrationRequest = $request;
            $promise = new Promise();
            $promise->resolve(new Response(200, [], $this->buildAppResponse($request)));

            return $promise;
        }

        if ($this->isRegistrationConfirmation($request)) {
            $this->confirmationRequest = $request;
            $promise = new Promise();
            $promise->resolve(new Response(200));