update cache.h to reflect changes, empty cache entries are illegal, and unknown-size is returned as 0
#ifndef SOCKET_H
#define SOCKET_H
#include "config.h"
#define SOCKET_LISTEN_BACKLOG 128
int socket_listen (struct config_endpoint *endpoint, int sock_type);
int socket_connect_async (struct config_endpoint *endpoint, int sock_type);
#endif /* SOCKET_H */