int server_start(ev_source *ev, int pf,
size_t socklen, const struct sockaddr *sa,
int server_start(ev_source *ev, int pf,
size_t socklen, const struct sockaddr *sa,
/* start listening. Return the fd. */
int server_stop(ev_source *ev, int fd);
/* start listening. Return the fd. */
int server_stop(ev_source *ev, int fd);