if (_listener != NULL) {
log_debug("send_message_and_wait_response(): %s, server_callback != NULL\n", msg_req_param);
_listener->request_received(msg_req_param, &msg_rsp);
if (_listener != NULL) {
log_debug("send_message_and_wait_response(): %s, server_callback != NULL\n", msg_req_param);
_listener->request_received(msg_req_param, &msg_rsp);