extern bool send_del_edge(struct connection_t *, const struct edge_t *);
extern bool send_key_changed(struct connection_t *, const struct node_t *);
extern bool send_req_key(struct connection_t *, const struct node_t *, const struct node_t *);
extern bool send_del_edge(struct connection_t *, const struct edge_t *);
extern bool send_key_changed(struct connection_t *, const struct node_t *);
extern bool send_req_key(struct connection_t *, const struct node_t *, const struct node_t *);