When we were using android coordinator layout, we could use anchor to a view in the layout using :

<FloatingActionButton
   app:layout_anchor="@id/appBar"
   app:layout_anchorGravity="bottom|end" />

Lets say we want to implement the same logic in compose. I have a DetailContent as follow which includes a button, and I want to anchor button to bottom of Toolbar.

@Composable
private fun DetailsContent(
    scrollState: ScrollState,
    onNamePosition: (Float) -> Unit,
    item: Poster,
    sendNotification: () -> Unit,
    contentAlpha: () -> Float,
) {
    Column(
        modifier = Modifier.verticalScroll(scrollState)
    ) {
        Box(
            modifier = Modifier.height(Dimens.DetailBoxImageHeight)
        ) {
            Image(
                painter = rememberImagePainter(item.poster),
                contentDescription = null,
                modifier = Modifier
                    .align(Alignment.TopCenter)
                    .fillMaxWidth()
                    .clip(shape = MaterialTheme.shapes.medium)
                    .alpha(contentAlpha()),
                contentScale = ContentScale.Crop,
            )
            Button(
                onClick = sendNotification,
                shape = RoundedCornerShape(36.dp),
                modifier = Modifier
                    .width(126.dp)
                    .align(Alignment.BottomCenter)
                    .offset(y = 23.5.dp)


            ) {
                Text(text = "DeepLink")
            }
        }
        Spacer(Modifier.height(32.dp))
        Text(
            modifier = Modifier.padding(8.dp),
            text = item.description,
            style = typography.body2,
            fontSize = 18.sp,
            color = MaterialTheme.colors.onSurface
        )
    }
}

So we have a DetailContent as well as DetailsToolbar :

Box(Modifier.fillMaxSize()) {
        DetailsContent(
            scrollState = scrollState,
            onNamePosition = { newNamePosition ->
                // Comparing to Float.MIN_VALUE as we are just interested on the original
                // position of name on the screen
                if (detailScroller.namePosition == Float.MIN_VALUE) {
                    detailScroller =
                        detailScroller.copy(namePosition = newNamePosition)
                }
            },
            item = item,
            sendNotification = sendNotification,
            contentAlpha = { contentAlpha.value }
        )
        DetailsToolbar(
            toolbarState, item.name, pressOnBack,
            contentAlpha = { contentAlpha.value }
        )
    }

How can I anchor the Button to DetailsToolbar ?