Description

It seems that we cannot configure symfony/messenger to prevent auto setup for delay exchange.

When an application is just a publisher but doesn't consume any queue, there is no need to auto setup a delay exchange.

I'm actually working on a PR about this.

Example

Proposal:
Add the option auto_setup for delay, default true.

framework:
    messenger:
        transports:
            async_transport:
        [...]
       
                # https://symfony.com/doc/current/messenger.html#amqp-transport
                options:
                    delay:
                        auto_setup: false
                    queues: []
[...]

With this option, the delay exchange will not be declared there:

Also, add a condition in Connection->setup to call setupDelayExchange only if delay exchange is not disabled (transport retry_strategy.max_retries equals 0 ? Not sure because delay may be use in other use cases than retry)