[tepl] FileMetadata: add comment

[Sébastien Wilmet <swilmet src gnome org>]

commit 1c59ddfb305dfcdf7005b3f64bfdd20b03b7e920
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Thu Apr 9 17:41:26 2020 +0200

    FileMetadata: add comment

 tepl/tepl-file-metadata.c | 4 ++++
 1 file changed, 4 insertions(+)
---
diff --git a/tepl/tepl-file-metadata.c b/tepl/tepl-file-metadata.c
index 597bc43..3e200c1 100644
--- a/tepl/tepl-file-metadata.c
+++ b/tepl/tepl-file-metadata.c
@@ -464,6 +464,10 @@ tepl_file_metadata_save_async (TeplFileMetadata    *metadata,
                return;
        }
 
+       /* The g_file_set_attributes_async() implementation calls
+        * g_file_info_dup(), so no need to take care about data races ourself
+        * (save_async() -> set() -> save_finish()).
+        */
        g_file_set_attributes_async (location,
                                     priv->file_info_modified,
                                     G_FILE_QUERY_INFO_NONE,