diff --git a/internal/internal.go b/internal/internal.go
index 6fd344b..756fc25 100644
--- a/internal/internal.go
+++ b/internal/internal.go
@@ -10,6 +10,9 @@ func RetryBackoff(retry int, minBackoff, maxBackoff time.Duration) time.Duration
 	if retry < 0 {
 		panic("not reached")
 	}
+	if minBackoff == 0 {
+		return 0
+	}
 
 	d := minBackoff << uint(retry)
 	d = minBackoff + time.Duration(rand.Int63n(int64(d)))