BarChartEvent
BarChartEvent class has the following values:
bar_index
Bar's index or -1 if chart is hovered or clicked outside of any bar.
rod_index
Rod's index or -1 if chart is hovered or clicked outside of any bar.
stack_item_index
Stack item's index or -1 if chart is hovered or clicked outside of any bar.
type
Event's type such as PointerHoverEvent, PointerExitEvent, etc.