+int pb_protocol_serialise_url(const char *url, char *buf, int buf_len);
+int pb_protocol_serialise_plugin_option(const struct plugin_option *opt,
+ char *buf, int buf_len);
+int pb_protocol_serialise_temp_autoboot(const struct autoboot_option *opt,
+ char *buf, int buf_len);
+int pb_protocol_serialise_authenticate(struct auth_message *msg,
+ char *buf, int buf_len);