open class ViewHolder(view: View, val action: ((Item) -> Unit)? = null) : RecyclerView.ViewHolder(view) {
    // ...
}

class AViewHolder(view: View, action: ((Item) -> Unit)? = null) : ViewHolder(view, action) {
    // ...
}

class BViewHolder(view: View, action: ((Item) -> Unit)? = null) : ViewHolder(view, action) {
    // ...
}