bool add_duplex(struct io_conn *c);
void del_listener(struct io_listener *l);
void backend_plan_changed(struct io_conn *conn);
+void backend_wait_changed(const void *wait);
void backend_add_timeout(struct io_conn *conn, struct timespec ts);
void backend_del_timeout(struct io_conn *conn);
void backend_del_conn(struct io_conn *conn);