restygwt/src/main/java/org/fusesource/restygwt/client/JsonpMethod.java
public Object send(AsyncCallback<JavaScriptObject> callback) {
        return jsonpBuilder.requestObject(resource.getUri(), callback);
    }
public Object send(AsyncCallback<JavaScriptObject> callback) {
        return jsonpBuilder.requestObject(resource.getUri(), callback);
    }
helper method to make RestServiceClassCreator easier to maintain
@param callback