src/vs/workbench/contrib/notebook/browser/services/notebookWorkerServiceImpl.ts/NotebookEditorModelManager/ensureSyncedResources
class NotebookEditorModelManager:	public ensureSyncedResources(resources: URI[]): void {
		for (const resource of resources) {
			const resourceStr = resource.toString();

			if (!this._syncedModels[resourceStr]) {
				this._beginModelSync(resource);
			}
			if (this._syncedModels[resourceStr]) {
				this._syncedModelsLastUsedTime[resourceStr] = (new Date()).getTime();
			}
		}
	}