Issue #3511950: Add interface for entity backed recipients

src/Recipients/Recipient/EmailRecipient.php

@@ -15,7 +15,7 @@ use Symfony\Component\Notifier\Recipient\EmailRecipientInterface;
  * You should implement your own class implementing EmailRecipientInterface if
  * you need an object like this.
  */
-final class EmailRecipient implements EmailRecipientInterface {
+final class EmailRecipient implements EmailRecipientInterface, EntityRecipientInterface {
 
   /**
    * @internal

src/Recipients/Recipient/EntityRecipientInterface.php

+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\notifier\Recipients\Recipient;
+
+use Drupal\Core\Entity\EntityInterface;
+use Symfony\Component\Notifier\Recipient\RecipientInterface;
+
+interface EntityRecipientInterface extends RecipientInterface {
+
+  public function getEntity(): EntityInterface;
+
+}

src/Recipients/Recipient/SmsRecipient.php

@@ -14,7 +14,7 @@ use Symfony\Component\Notifier\Recipient\SmsRecipientInterface;
  * You should implement your own class implementing SmsRecipientInterface if
  * you need an object like this.
  */
-final class SmsRecipient implements SmsRecipientInterface {
+final class SmsRecipient implements SmsRecipientInterface, EntityRecipientInterface {
 
   /**
    * @internal