+int sd_bus_add_object(sd_bus *bus, const char *path, sd_message_handler_t callback, void *userdata);
+int sd_bus_remove_object(sd_bus *bus, const char *path, sd_message_handler_t callback, void *userdata);
+
+int sd_bus_add_fallback(sd_bus *bus, const char *prefix, sd_message_handler_t callback, void *userdata);
+int sd_bus_remove_fallback(sd_bus *bus, const char *prefix, sd_message_handler_t callback, void *userdata);
+