Fixes: #3040Resolves#3041
This change adds out-of-the-box `ListenerContainerCustomizer<AbstractMessageListenerContainer>`
to set `VirtualThreadTaskExecutor` into an `AbstractMessageListenerContainer` created by the binder
when `Threading.VIRTUAL` condition is met
Fixes: https://github.com/spring-cloud/spring-cloud-stream/issues/2939
The RabbitMQ 4.0 does not deal with client side `x-*` headers.
Therefore, an `x-death.count` is not incremented anymore when
message is re-published from client back to the broker.
* Spring AMQP 3.2 has introduced an `AmqpHeaders.RETRY_COUNT` custom header.
Use `messageProperties.incrementRetryCount()` in the `RabbitMessageChannelBinder`
when we re-published message back to the broker for server-side retries
* Fix docs respectively
Resolves#3019
Fixes: #2901
* Rework an observation for Rabbit Binder
The observation propagation doesn't work in multi-binder configuration
* Remove `ObservationAutoConfiguration` since it is not visible in case of multi-binder configuration
* Instead move `setObservationEnabled` flag setting to the `RabbitMessageChannelBinder`
* Add `io.micrometer.observation.ObservationRegistry` into `shared.beans` to make it visible for binder-specific application context
* Add `RabbitMultiBinderObservationTests` integration test where Rabbit Binder is in a multi-binder environment
As a side effect, this fixes an observation propagation for the Kafka binder as well in the multi-binder environment.
Its configuration is OK, but an `ObservationRegistry` must make it visible for the binder-specific application context.
See the mentioned `shared. beans`
Related to https://github.com/spring-cloud/spring-cloud-stream/issues/2901
Also see https://github.com/spring-cloud/spring-cloud-stream/issues/2902 for possible evolution
* Update the copyright of the affected classes
