[Question] [LineChart] Its possible to know the barIndex in getTouchedSpotIndicator

Hi again @imaNNeoFighT,

I want to customize the point when I touch, for each of the lines.
For line 0 I want the blue point, for line 1 I want the green point.

**Is it possible to access the line index ??**


I tried it this way but it gives me the error I mentioned in the code.


### Congratulations on the library once again.

**Versions**
**Flutter version:** 1.22.0
**FlChart version:** 0.12.0

Start with the LineChart getTouchedSpotIndicator API described in the issue and reproduce the reported error using Flutter 1.22.0 and fl_chart 0.12.0. The payload names no files or tests; done means establishing whether line-specific colors are supported and documenting the answer or defining a verifiable API change.

Written by the indexing model from the issue text.