CollectionViewControllerLocalDrag.swift

coordinator.session.loadObjects(ofClass: Cat.self) { cats in
  DispatchQueue.main.async {
    if coordinator.session.localDragSession != nil, let previousIndex = self.viewModel.cats.index(where: { $0.name == cat.name }) {
      //Local drag session
      self.viewModel.cats.swapAt(previousIndex, destinationIndexPath.row)
    } else {
      // External drag session
      self.viewModel.cats.insert(cat, at: destinationIndexPath.row)
    }
    collectionView.reloadSections(destinationIndexPath.section)
  }
}