Scaffold(
    floatingActionButton = {
            val showFab = listState.isScrollingUp().value
            println("showing fab: $showFab")
            AnimatedVisibility(visible = showFab) {
                FloatingActionButton(
                    onClick = {
                        ...
                    }
                ) {
                    Icon(
                        imageVector = Icons.Default.Add,
                        contentDescription = "add"
                    )
                }
            }
    },
    ...
)