When a for statement is executed, a cursor is implicitly declared such that for each iteration of the forloop, the next row is the result set if fetched.
在执行for语句时，游标被隐式声明，这样对于FOR循环的每一次迭代，取回的下一行就是结果集。
2
Finally, we make the starting offset for the nextloop the ending offset of the current one.
最后，我们将当前的结束偏移量设置为下一个循环的开始偏移量。
3
The nextforloop processes just the HTTP links only.