+int sd_bus_message_read_basic(sd_bus_message *m, char type, void *p);
+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);
+int sd_bus_message_rewind(sd_bus_message *m, int complete);