extra line with some additional details

I used this package in one of my flutter project and want extra lines with some additional details. How can I achieve this?

UI Reference:

The issue provides only a UI reference and does not name a file, test, or entry point. Start by identifying the Flutter chart widget and existing configuration for labels or annotations, then clarify which extra lines and details are required; done means the requested layout is supported and covered by an appropriate test or example.

Written by the indexing model from the issue text.