Description

Hello,

Messenger is a great component, but has some drawbacks when it comes to send messages across different apps which use messenger.
Let's pretend an app A sends message through rabbitMQ, that will be consumed by an app B

Messages needs to be "sanitized" before leaving the app:

• stamps should be removed: if a stamp exists in app A and not in app B, when A sends messages to B, an error could occur. As well as if app A uses a bus which not exist in app B, B will try to get a bus which does not exist and an error will be thrown.
• header type could also be problematic: if PHP message objects in both apps do not have the same FQCN, when app B receives the message it will try to deserialize it in a class which does not exist.

A solution would be to add a new interface ExternalMessageInterface and take some actions when the interface is encountered in \Symfony\Component\Messenger\Transport\Serialization\Serializer.

I don't think we could fix this with a middleware, because the header type is added at serialization time.

I'd like to have some feedback on this before fixing it.

Thanks :)