int sd_bus_negotiate_timestamp(sd_bus *bus, int b);
int sd_bus_negotiate_creds(sd_bus *bus, int b, uint64_t creds_mask);
int sd_bus_get_creds_mask(sd_bus *bus, uint64_t *creds_mask);
int sd_bus_negotiate_timestamp(sd_bus *bus, int b);
int sd_bus_negotiate_creds(sd_bus *bus, int b, uint64_t creds_mask);
int sd_bus_get_creds_mask(sd_bus *bus, uint64_t *creds_mask);