Fix: api comments (#867)

Author: LaurenceLiZhixin

api.go

@@ -54,10 +54,10 @@ func NewTransactionProducer(listener primitive.TransactionListener, opts ...prod
 }
 
 type PushConsumer interface {
-	// Start the PullConsumer for consuming message
+	// Start the PushConsumer for consuming message
 	Start() error
 
-	// Shutdown the PullConsumer, all offset of MessageQueue will be sync to broker before process exit
+	// Shutdown the PushConsumer, all offset of MessageQueue will be sync to broker before process exit
 	Shutdown() error
 	// Subscribe a topic for consuming
 	Subscribe(topic string, selector consumer.MessageSelector,