consumer shutdown will result in unspent mark consumption success

if consumer all return ConsumeRetryLater, when consumer run consumer.shutdown. View message trace The message was successfully consumed

` err = cs.Subscribe("topic", selector, func(ctx context.Context, ext ...*primitive.MessageExt) (consumer.ConsumeResult, error) {
for i := range ext {
fmt.Printf("%+v\n", ext[i])
}
return consumer.ConsumeRetryLater, nil
})
if err != nil {
fmt.Println(err)
}`