      - parameter handler: Error handler to execute when an error occurs.
      - returns: Self instance to support chaining.
     */
-    @objc public func updateErrorUIObjC(_ handler: @escaping (NSError) -> Void) -> Self {
+    @discardableResult @objc public func updateErrorUIObjC(_ handler: @escaping (NSError) -> Void) -> Self {
         return updateErrorUI { error in
             handler(error as NSError)
         }

     - parameter handler: Error handler to execute when an error occurs.
     - returns: Self instance to support chaining.
    */
    @objc public func responseErrorObjC(_ handler: @escaping (NSError) -> Void) -> Self {
        return responseError { error in
            handler(error as NSError)
        }

     - parameter handler: Response handler to execute upon receiving a response.
     - returns: Self instance to support chaining.
     */
    @discardableResult @objc public func responseJSONObjC(_ handler: @escaping (Any, URLResponse?) -> ObjCHandlerResult?) -> Self {
        return responseJSON { json, response in
            return ServiceTaskResult(objCHandlerResult: handler(json, response))
        }
