Mine

            if (icd_caller__has_role(that, ICD_AGENT_ROLE)) {
                if (!icd_caller__get_onhook(that)) {
                    result = ast_streamfile(that->chan, "beep", that->chan->language);

                    if(icd_caller__get_acknowledge_call(that)) {
                        if(icd_bridge_wait_ack(that) < 0) {
                                //...
                        }
                    }

                    if (!result)
                        result = ast_waitstream(that->chan, AST_DIGIT_ANY);
                }
            }