The average size of the retransmit queue can be calculated from the packets scanned counter if the number of SACK options sent is also tracked at the client.
如果在客户机可以跟踪发出的SACK选项的数目，则重传队列的大小可从扫描包计数器中计算得到。
2
If it's a TransactionMsg, then the list of modified rows is accessed, and the counter is updated by the size of the list.
如果它是一个TransactionMsg，那么就访问修改行的列表，并用该列表的大小来更新计数器。
3
The HCCountHandler class is half the size of SAXCounterHandler, and most of the code deals with the counter.