1 files changed, 1 insertions, 1 deletions

diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py

index a5734bebab..262901363f 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -86,7 +86,7 @@ from synapse.visibility import filter_events_for_server
 logger = logging.getLogger(__name__)
 
 
-@attr.s
+@attr.s(slots=True)
 class _NewEventInfo:
     """Holds information about a received event, ready for passing to _handle_new_events