new file mode 100644
--- /dev/null
+++ b/stats.h
@@ -0,0 +1,8 @@
+/* stats */
+void stats_prefix_init(void);
+void stats_prefix_clear(void);
+void stats_prefix_record_get(const char *key, const bool is_hit);
+void stats_prefix_record_delete(const char *key);
+void stats_prefix_record_set(const char *key);
+/*@null@*/
+char *stats_prefix_dump(int *length);