BarChart: get bar index on touch?

[Darksoulsong]

fl_chart: ^0.12.2 here.

I need to be able to run a callback on touching a BarChart's bar, and I'm using touchCallback to handle this. I'd like to get info that would tell me which bar has been touched, like an index, and tried to use barTouchResponse.spot, but it's value is always null.

Is it possible?