Merge pull request #38 from fractalzombie/bugfix/undefined_property_h…

…eaders

Fix headers in KafkaReceiver.php on line 64.

src/Messenger/KafkaReceiver.php

@@ -61,7 +61,7 @@ public function get(): iterable
 
                 $envelope = $this->serializer->decode([
                     'body' => $message->payload,
-                    'headers' => $message->headers,
+                    'headers' => $message->headers ?? [],
                     'key' => $message->key,
                     'offset' => $message->offset,
                     'timestamp' => $message->timestamp,