proc_get_peer_uid
uid = proc_get_peer_uid(c->peer);
uid = proc_get_peer_uid(loop->peer);
uid = proc_get_peer_uid(ft->c->peer);
uid = proc_get_peer_uid(ft->c->peer);
uid = proc_get_peer_uid(c->peer);
uid = proc_get_peer_uid(c->peer);
uid = proc_get_peer_uid(c->peer);
uid_t proc_get_peer_uid(struct tmuxpeer *);