Note - please see an update on this below.
It is available on FlexColumn. Use it inside Column, like this:
@Preview
@Composable
fun NewsStory() {
Column( modifier=Spacing(16.dp)) {
FlexColumn(
crossAxisSize = LayoutSize.Expand
)
{
Text("demo")
Text("try")
Text("somethings")
}
}
}
I assume this is the result you want?

FlexColumn:
@Composable fun FlexColumn(
modifier: Modifier = Modifier.None,
mainAxisAlignment: MainAxisAlignment = MainAxisAlignment.Start,
crossAxisAlignment: CrossAxisAlignment = CrossAxisAlignment.Start,
crossAxisSize: LayoutSize = LayoutSize.Wrap,
block: FlexChildren.() -> Unit
): Unit
link here
EDIT - Important:
Just came to know that Flex is going to be deprecated soon. Oh the joy of working with alpha releases (: So the correct way would be to use Column/Row and apply Flexible modifier to the children. Keeping this post instead of deleting as someone might still be tempted to use FlexColumn/FlexRow as they are still officially out there. Do not!