# Insert an \hline once, after the nth row in pgfplotstable

In the pgfplotstable documents, there is an example where you can input \hlines in every couple rows:

\pgfplotstabletypeset[
every nth row={3}{before row=\hline},  % insert hline every 3 rows
every head row/.style={before row=\hline, after row=\hline},
every last row/.style={after row=\hline},
]{
a b
0 0
1 1
2 2
3 3
4 4
5 5
6 6
7 7
8 8
}


How can I insert an hline once only after the third row, instead of every third?

every row no 3/.style={before row=\hline}