int sd_bus_message_read(sd_bus_message *m, const char *types, ...);
int sd_bus_message_read_basic(sd_bus_message *m, char type, void *p);
int sd_bus_message_read_array(sd_bus_message *m, char type, const void **ptr, size_t *size);
+int sd_bus_message_skip(sd_bus_message *m, const char *types);
int sd_bus_message_enter_container(sd_bus_message *m, char type, const char *contents);
int sd_bus_message_exit_container(sd_bus_message *m);
int sd_bus_message_peek_type(sd_bus_message *m, char *type, const char **contents);