GooglePubSubProducer does some conversion of the message body before it gets sent to the destination topic, so that is of the expected ByteString type.
If the payload is String or byte, then the conversion is simple. Any other type is serialized via ObjectOutputStream.
This is problematic for camel-quarkus and native support because JDK serialization via ObjectOutputStream is not supported. Hence, it'd be nice if there was a way to provide a custom serializer that uses an alternate mechanism. E.g one that uses Jackson -> JSON etc.