src/vs/workbench/contrib/interactive/browser/interactiveEditorInput.ts/serializeCell
function serializeCell(cell: NotebookCellTextModel): ISerializedCell {
	return {
		cellKind: cell.cellKind,
		language: cell.language,
		metadata: cell.metadata,
		mime: cell.mime,
		outputs: cell.outputs.map(output => serializeCellOutput(output)),
		source: cell.getValue()
	};
}