From b40c125492813e5fb656ee9da4d91473726be5d8 Mon Sep 17 00:00:00 2001
From: Marty Schoch <marty.schoch@gmail.com>
Date: Fri, 22 Jan 2021 11:37:03 -0500
Subject: [PATCH] introduce new optional interface for backup

---
 index.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/index.go b/index.go
index 1497919..ca34285 100644
--- a/index.go
+++ b/index.go
@@ -78,6 +78,10 @@ type IndexReader interface {
 	Close() error
 }
 
+type IndexReaderBackupable interface {
+	Backup(string) error
+}
+
 type IndexReaderRegexp interface {
 	FieldDictRegexp(field string, regex string) (FieldDict, error)
 }