secondaryTrackValue property
final
The secondary track value for this slider.
If not null, a secondary track using Slider.secondaryActiveColor color is drawn between the thumb and this value, over the inactive track.
If less than Slider.value, then the secondary track is not shown.
It can be ideal for media scenarios such as showing the buffering progress while the Slider.value shows the play progress.
Implementation
final double? secondaryTrackValue;