The service contract type ESB in Switchyard is not intuitive and the current documentation doesn't give further explanation about it. It's briefly mentioned on Section 3.4 of Development_Guide_Volume_1_SwitchYard (manual identifier) and that's all.
Found this community discussion useful: https://community.jboss.org/thread/235374
However, it's not complete. Users must have wider understanding of it and how to put in to work.
Thank you for your feedback.
This is already a known issue and has been marked as high priority.
Closing as a duplicate.
*** This bug has been marked as a duplicate of bug 1121477 ***