A delegate to update RecycletView's adapter data with DiffUtil

DiffUtilDelegate.kt

class DiffUtilDelegate<T, VH : RecyclerView.ViewHolder, A : RecyclerView.Adapter<VH>>(
        initialValue: List<T>,
        private val callbackFactory: (List<T>, List<T>) -> DiffUtil.Callback =
                { old, new -> SimpleCallback(old, new) }
) {

    private var currentValue: List<T> = initialValue

    operator fun setValue(thisRef: A?, property: KProperty<*>, value: List<T>) {
        val callback = callbackFactory(currentValue, value)
        val diff = DiffUtil.calculateDiff(callback)
        thisRef?.let { diff.dispatchUpdatesTo(it) }
        currentValue = value
    }

    operator fun getValue(thisRef: Any?, property: KProperty<*>): List<T> = currentValue

}

class SimpleCallback<T>(
    private val oldList: List<T>,
    private val newList: List<T>,
    private val areItemsTheSame: ((oldItem: T, newItem: T) -> Boolean)? = null,
    private val areContentsTheSame: ((oldItem: T, newItem: T) -> Boolean)? = null,
    private val getChangePayload: ((oldItem: T, newItem: T) -> Any?)? = null
) : DiffUtil.Callback() {

    override fun areItemsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
        return areItemsTheSame?.invoke(
            oldList[oldItemPosition],
            newList[newItemPosition]
        ) ?: oldList[oldItemPosition] == newList[newItemPosition]
    }

    override fun areContentsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
        return areContentsTheSame?.invoke(
            oldList[oldItemPosition],
            newList[newItemPosition]
        ) ?: oldList[oldItemPosition] == newList[newItemPosition]
    }

    override fun getChangePayload(oldItemPosition: Int, newItemPosition: Int): Any? {
        return getChangePayload?.invoke(oldList[oldItemPosition], newList[newItemPosition])
    }

    override fun getOldListSize(): Int = oldList.size

    override fun getNewListSize(): Int = newList.size

}