code: @SuppressWarnings("unchecked")
      public static <Item extends IItem> Item getHolderAdapterItemTag(@Nullable RecyclerView.ViewHolder holder) {
          if (holder != null) {
              Object item = holder.itemView.getTag(com.mikepenz.fastadapter.R.id.fastadapter_item);
              if (item instanceof IItem) {
                  return (Item) item;
              }
          }
          return null;
      }
docs: convenient helper method to get the Item from a holder via the defined tag
  
  @param holder the ViewHolder for which we want to retrieve the item
  @return the Item found for the given position and that ViewHolder