typedef int (*utcp_send_t)(struct utcp *utcp, void *data, size_t len);
typedef int (*utcp_recv_t)(struct utcp_connection *connection, void *data, size_t len);
extern struct utcp *utcp_init(utcp_accept_t accept, utcp_pre_accept_t pre_accept, utcp_send_t send, void *priv);
extern void utcp_exit(struct utcp *utcp);
typedef int (*utcp_send_t)(struct utcp *utcp, void *data, size_t len);
typedef int (*utcp_recv_t)(struct utcp_connection *connection, void *data, size_t len);
extern struct utcp *utcp_init(utcp_accept_t accept, utcp_pre_accept_t pre_accept, utcp_send_t send, void *priv);
extern void utcp_exit(struct utcp *utcp);