diff --git a/bencode/decode.go b/bencode/decode.go
index 76800d65..d0b857ce 100644
--- a/bencode/decode.go
+++ b/bencode/decode.go
@@ -17,6 +17,7 @@ type Decoder struct {
 		io.ByteScanner
 		io.Reader
 	}
+	// Sum of bytes used to Decode values.
 	Offset int64
 	buf    bytes.Buffer
 	key    string