Fix thread safety issues

Author: lixizan

event.go

@@ -85,7 +85,7 @@ func (c *EventEmitter) Publish(ctx context.Context, topic string, msg any) error
 	defer t.Unlock()
 
 	for _, v := range t.subs {
-		if cb, ok := v.topics[topic]; ok {
+		if cb, exist := v.GetTopic(topic); exist {
 			if err := t.Emit(ctx, msg, cb); err != nil {
 				return err
 			}

types.go

@@ -58,3 +58,10 @@ func (c *subscriberField) Delete(k string) int {
 	c.Unlock()
 	return n
 }
+
+func (c *subscriberField) GetTopic(topic string) (cb eventCallback, exist bool) {
+	c.Lock()
+	cb, exist = c.topics[topic]
+	c.Unlock()
+	return
+}