[TASK] Add very basic usage example for TYPO3

Fixes #6

README.md

@@ -68,6 +68,11 @@ For more information about the HTTP API see the [official documentation](https:/
 
 You can access the RabbitMQ service through its AMQP protocol inside any DDEV container via `amqp://rabbitmq:5672`
 
+## Examples:
+
+* [TYPO3](USAGE.md)
+
+
 **Originally Contributed by [@Graloth](https://github.com/Graloth) in [ddev-contrib](https://github.com/ddev/ddev-contrib/tree/master/docker-compose-services/rabbitmq)**
 
 **Maintained by [@b13](https://github.com/b13)**

USAGE.md

@@ -0,0 +1,82 @@
+# TYPO3 and RabbitMQ 
+
+This is just a simple example on how RabbitMQ can be used
+along with TYPO3.
+
+Install required package:
+
+```bash
+ddev composer req symfony/amqp-messenger
+```
+
+Create a message with all information needed later on in the handler:
+
+```php
+final class MyMessage
+{
+    public function __construct(
+        public readonly array $content
+    ) {
+    }
+}
+```
+
+Process a message:
+
+```php
+final class MyHandler
+{
+    public function __construct(private readonly MessageBusInterface $bus)
+    {
+    }
+
+    public function __invoke(MyMessage $message): void
+    {
+        try {
+            // #### Do magic stuff with $message->content ####
+        } catch (\Exception $exception) {
+            // Workaround to support infinite retryable messages. So no message gets lost.
+            $envelope = new Envelope(new MyMessage($message->content), [new DelayStamp(5000)]);
+            $this->bus->dispatch($envelope);
+        }
+    }
+}
+```
+
+Register 'amqp' in ext_localconf.php
+
+```php
+// Unset the default, so that it no longer applies
+unset($GLOBALS['TYPO3_CONF_VARS']['SYS']['messenger']['routing']['*']);
+// Set Webhook-Messages and MyMessage to asynchronous transport via amqp
+foreach ([WebhookMessageInterface::class, MyMessage::class] as $className) {
+    $GLOBALS['TYPO3_CONF_VARS']['SYS']['messenger']['routing'][$className] = 'amqp';
+}
+```
+
+Dispatch a message:
+
+```php
+class RunTheRabbit implements MiddlewareInterface
+{
+    public function __construct(private readonly MessageBusInterface $bus)
+    {
+    }
+
+    public function process(
+        ServerRequestInterface $request,
+        RequestHandlerInterface $handler
+    ): ResponseInterface {
+        $value = ['some' => 'value'];
+        $this->bus->dispatch(new MyMessage($value));
+
+        return $handler->handle($request);
+    }
+}
+```
+
+Start the worker to consume messages:
+
+```bash
+ddev typo3 messenger:consume -vv amqp
+```