Use Spring Boot autoconfigure-processor to optimize auto-configurations

[bclozel]

As explained in the its reference documentation, Spring Boot provides a spring-boot-autoconfigure-processor.

This should be added as an optional dependency to the module that contains the AutoConfiguration classes (and contains the spring.factories file declaring them).

Once configured, this annotation processor will generate metadata at compile time and will help Spring Boot process those auto-configurations without loading the actual classes in some cases.

The spring-cloud-stream and spring-cloud-stream-reactive are declaring at least one auto-configuration but don't use this annotation processor. Could you add it to the build?

<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-autoconfigure-processor</artifactId>
	<optional>true</optional>
</dependency>

Once added, this should generate a spring-autoconfigure-metadata.properties file in the target/classes/META-INF folders.