Added remarks

app/src/main/java/eu/faircode/email/Core.java

@@ -1380,6 +1380,7 @@ class Core {
             IMAPFolder ifolder, IMAPMessage imessage,
             boolean browsed, boolean download,
             List<EntityRule> rules, State state) throws MessagingException, IOException {
+        // Instead of locking the database while performing message I/O
         lockFolders.putIfAbsent(folder.id, folder.id);
         synchronized (lockFolders.get(folder.id)) {
             long uid = ifolder.getUID(imessage);
@@ -2206,6 +2207,8 @@ class Core {
                             .setVisibility(NotificationCompat.VISIBILITY_PRIVATE)
                             .setOnlyAlertOnce(true);
 
+            // TODO: setAllowSystemGeneratedContextualActions
+
             if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N)
                 mbuilder
                         .setGroup(Long.toString(group))