add new attribut to MessageOutgoingEvent to allow logging configuration

src/common/connection.py

@@ -1781,6 +1781,8 @@ class Connection(CommonConnection, ConnectionHandlers):
             if obj.callback:
                 obj.callback(msg_id, *obj.callback_args)
 
+            if not obj.is_loggable:
+                return
             self.log_message(jid, msg, forward_from, session, original_message,
                     subject, type_)
 

src/common/connection_handlers_events.py

@@ -2067,6 +2067,7 @@ class MessageOutgoingEvent(nec.NetworkIncomingEvent):
         self.callback = None
         self.callback_args = []
         self.now = False
+        self.is_loggable = True
 
     def generate(self):
-        return True
+        return True