fix(bus): prevent double close in event dispatcher

pkg/bus/memory/event_dispatcher.go

@@ -83,8 +83,12 @@ func (d *eventDispatcher) Close() {
 }
 
 func (d *eventDispatcher) close() {
-	d.closed = true
+	if d.closed {
+		return
+	}
+
 	close(d.in)
+	d.closed = true
 }
 
 func (d *eventDispatcher) In(msg bus.Message) (err error) {