src/vs/workbench/contrib/notebook/browser/viewModel/notebookViewModelImpl.ts/NotebookViewModel/_withElement
class NotebookViewModel:	private async _withElement(element: SingleModelEditStackElement | MultiModelEditStackElement, callback: () => Promise<void>) {
		const viewCells = this._viewCells.filter(cell => element.matchesResource(cell.uri));
		const refs = await Promise.all(viewCells.map(cell => this._textModelService.createModelReference(cell.uri)));
		await callback();
		refs.forEach(ref => ref.dispose());
	}