src/vs/editor/common/model/editStack.ts/MultiModelEditStackElement/constructor
class MultiModelEditStackElement:	constructor(
		public readonly label: string,
		public readonly code: string,
		editStackElements: SingleModelEditStackElement[]
	) {
		this._isOpen = true;
		this._editStackElementsArr = editStackElements.slice(0);
		this._editStackElementsMap = new Map<string, SingleModelEditStackElement>();
		for (const editStackElement of this._editStackElementsArr) {
			const key = uriGetComparisonKey(editStackElement.resource);
			this._editStackElementsMap.set(key, editStackElement);
		}
		this._delegate = null;
	}