typealias Callback = (String) -> Unit

// Fixme: composition policy
val LocalActiveCallback = compositionLocalOf<Callback> { error("No active callback") }

@Composable
@Preview
fun Parent() {
    val callback: Callback = { msg ->
        Timber.e(msg)
    }

    CompositionLocalProvider(LocalActiveCallback provides callback) {
        Child()
    }
}

@Composable
private fun Child() {
    val callback = LocalActiveCallback.current

    Button(onClick = {
        callback("hello")
    }) {
        Text("call me")
    }
}