// basic header based one.
$container->register('http_middleware.negotiation', 'Drupal\accept_header_routing_test\AcceptHeaderMiddleware')
->addTag('http_middleware', ['priority' => 400]);
// basic header based one.
$container->register('http_middleware.negotiation', 'Drupal\accept_header_routing_test\AcceptHeaderMiddleware')
->addTag('http_middleware', ['priority' => 400]);