Add Callback Content and Response[edit]
Below the callback path, we specify the method of the callback message and define the message format and the expected responses. These definitions are similar to regular request and response definitions.
To add the callback method, right mouse click on the callback path, then select New Operation.
Add Callback Method Request Body
To add the request body of the callback method, select the method, then select the Request Bodies tab.
Add Callback Method Response
To add a response to some callback method, select the method, then select the responses tab.