adapter.submitList(items.toMutableList())

class AppDiffCallback : DiffUtil.ItemCallback<Item?>() {

override fun areItemsTheSame(oldItem: Item, newItem: Item): Boolean {
    Timber.i("areItemsTheSame: called..")
    if (oldItem.getItemType() == newItem.getItemType()) {
        Timber.i("areItemsTheSame: done true..")
        return true
    }
    Timber.w("areItemsTheSame: done false..")
    return false
}

override fun areContentsTheSame(oldItem: Item, newItem: Item): Boolean {
    Timber.i("areContentsTheSame: called")
    if(oldItem.getItemType() != newItem.getItemType()){
        Timber.w("areContentsTheSame: itemsNotTheSame WTF???}")
        return false
    }

    return when (oldItem.getItemType()) {
        Item.HEADER -> checkHeaderContent(oldItem = oldItem as ItemHeader, newItem = newItem as ItemHeader)
        Item.ITEM_ACTION -> checkItemContent(oldItem = oldItem as ItemAction, newItem = newItem as ItemAction)
        else -> false
    }
}

   private fun checkHeaderContent(oldItem: ItemHeader, newItem:
     ItemHeader): Boolean {
         val itemContentTheSame = oldItem.date.toDate().time ==
         newItem.date.toDate().time
         return itemContentTheSame
   }

   private fun checkItemContent(oldItem: ItemAction, newItem: ItemAction): Boolean {
        val itemContentTheSame = oldItem.action == newItem.action
        return itemContentTheSame
   }
}