[pubsub] publish in parallel in memory implementation

Author: capcom6

pkg/pubsub/memory.go

@@ -49,19 +49,26 @@ func (m *memoryPubSub) Publish(ctx context.Context, topic string, data []byte) e
 		return nil
 	}
 
+	wg := &sync.WaitGroup{}
 	msg := Message{Topic: topic, Data: data}
+
 	for _, ch := range subscribers {
-		select {
-		case ch <- msg:
-		case <-ctx.Done():
-			return ctx.Err()
-		case <-m.closeCh:
-			return ErrPubSubClosed
-		default:
-			// subscriber buffer is full
-		}
+		wg.Add(1)
+		go func(ch chan Message) {
+			defer wg.Done()
+
+			select {
+			case ch <- msg:
+			case <-ctx.Done():
+				return
+			case <-m.closeCh:
+				return
+			}
+		}(ch)
 	}
 
+	wg.Wait()
+
 	return nil
 }