https://docs.spring.io/spring-integration/docs/current/reference/html/
https://docs.spring.io/spring-integration/docs/current/reference/html/index.html
https://docs.spring.io/spring-integration/docs/current/reference/html/index-single.html
https://docs.spring.io/spring-integration/docs/current/reference/pdf/spring-integration-reference.pdf

@MessagingGateway
@Gateway

org.springframework.integration.dsl.IntegrationFlow;