This is used by RenderSliverFloatingPersistentHeader to only expand when the user is scrolling in the same direction as the detected scroll offset change.
- forward → const ScrollDirection
Scrolling is happening in the positive scroll offset direction.
- idle → const ScrollDirection
No scrolling is underway.
- reverse → const ScrollDirection
Scrolling is happening in the negative scroll offset direction.
→ const List<
A constant List of the values in this enum, in order of their declaration.