collapsedFraction
A value that represents the collapsed height percentage of the app bar.
A 0.0 represents a fully expanded bar, and 1.0 represents a fully collapsed bar (computed as heightOffset / heightOffsetLimit).
A value that represents the collapsed height percentage of the app bar.
A 0.0 represents a fully expanded bar, and 1.0 represents a fully collapsed bar (computed as heightOffset / heightOffsetLimit).