How do I use Symfony Messenger for queues?

use Symfony\Component\Messenger\MessageBusInterface;
use Symfony\Component\Messenger\Handler\MessageHandlerInterface;
use Symfony\Component\Messenger\Transport\TransportInterface;

// Message Class
class MyMessage {
    private $content;

    public function __construct(string $content) {
        $this->content = $content;
    }

    public function getContent(): string {
        return $this->content;
    }
}

// Handler
class MyMessageHandler implements MessageHandlerInterface {
    public function __invoke(MyMessage $message) {
        echo 'Received message: ' . $message->getContent();
    }
}

// Sending a message
$bus = // ... get your message bus from the container
$message = new MyMessage('Hello, Symfony Messenger!');
$bus->dispatch($message);