src/vs/editor/common/model/editStack.ts/MultiModelEditStackElement/setModel
class MultiModelEditStackElement:	public setModel(model: ITextModel | URI): void {
		const key = uriGetComparisonKey(URI.isUri(model) ? model : model.uri);
		if (this._editStackElementsMap.has(key)) {
			this._editStackElementsMap.get(key)!.setModel(model);
		}
	}