Why is the consumer acknowledged in batches?

[llwwbb]

According to the Java example of the official website documentation, it should be possible to ack each message individually, like

MessageListener messageListener = new MessageListener() {
      @Override
      public ConsumeResult consume(MessageView messageView) {
          System.out.println(messageView);
          // Return the status based on the consumption result. 
          return ConsumeResult.SUCCESS;
      }
  };