The ExternalCallbackTarget interface is a marker interface that should be
placed on any control implementation (JCS) class that can be the target
of an asynchronous external callback.
The EndpointMethdodName annotation is only used when the JaxRpc Service Endpoint Interface method
does not match the method name on the service control.
Optional annotation indicating that the user will explicitly wrap the
DOC/LIT/WRAP parameters in objects that correspond to elements
in the original WSDL.