This relates to #30540, where we're pushing forward the last details to make Messenger really shine.

I think that a few transport-related options should be universally supported by all/whatever transports Symfony offers. For example:

• message priority
• number of retries
• delivery delay

The idea is to identify a few "features" that are typically standard in a transport (e.g. AMQP), and them create a TransportConfiguration stamp that allows you to configure those on a message-by-message basis. We would then work to make sure all transports support at least these features (or, if it's not possible/unreasonable, document which transports support which features, at least).

Thoughts?