make the StatusError language tag optional
diff --git a/client.go b/client.go
index 8ee052e..8f84670 100644
--- a/client.go
+++ b/client.go
@@ -1110,7 +1110,7 @@
 	}
 	code, data := unmarshalUint32(data)
 	msg, data := unmarshalString(data)
-	lang, _ := unmarshalString(data)
+	lang, _, _ := unmarshalStringSafe(data)
 	return &StatusError{
 		Code: code,
 		msg:  msg,