**Redirect:**

```php
use Drupal\Core\Url;  
use Symfony\Component\HttpFoundation\RedirectResponse;

$url = Url::fromUri('internal:/');  
$response = new RedirectResponse($url->toString());  
$response->send();
```

**Messeges using static service:**

`\Drupal::messenger()->addStatus($message);`

**Other equivalents:**

`addMessage()`   
`addError()`  
`addWarning()`  

**References:**

[RedirectResponse][1]  
[Url][2]  
[Drupal::messenger][3]  
[MessengerInterface][4]


  [1]: https://api.drupal.org/api/drupal/vendor%21symfony%21http-foundation%21RedirectResponse.php/class/RedirectResponse/8.5.x
  [2]: https://api.drupal.org/api/drupal/core!lib!Drupal!Core!Url.php/class/Url/8.5.x
  [3]: https://api.drupal.org/api/drupal/core%21lib%21Drupal.php/function/Drupal%3A%3Amessenger/8.5.x
  [4]: https://api.drupal.org/api/drupal/core%21lib%21Drupal%21Core%21Messenger%21MessengerInterface.php/interface/MessengerInterface/8.5.x