calculate_offset_progress.kt

...
var headerOffset: Float by mutableFloatStateOf(0f)
        private set
var progress: Float by mutableFloatStateOf(1f)
        private set
...
override fun onPreScroll(available: Offset, source: NestedScrollSource): Offset {
...
  val newOffset = headerOffset + delta
  val previousOffset = headerOffset
  val heightDelta = -(maxHeight - minHeight)
  headerOffset = if (heightDelta > 0) 0f else newOffset.coerceIn(heightDelta, 0f)
  progress = 1f - headerOffset / -maxHeight
  val consumed = headerOffset - previousOffset
  return Offset(0f, consumed)
...