private function validateServerRequest(RequestInterface $request)
{
if ($request instanceof ServerRequestInterface) {
return true;
}
throw new Exception\InvalidRequestTypeException(sprintf('Invoking callable middleware or final handler following http-interop ' . 'middleware, but did not receive a %s; please ensure that your ' . 'middleware always calls %s::process() using one.', ServerRequestInterface::class, DelegateInterface::class));
}