src/vs/workbench/contrib/notebook/common/services/notebookWorkerServiceImpl.ts/NotebookWorkerClient/_getOrCreateModelManager
class NotebookWorkerClient:	private _getOrCreateModelManager(proxy: NotebookEditorSimpleWorker): NotebookEditorModelManager {
		if (!this._modelManager) {
			this._modelManager = this._register(new NotebookEditorModelManager(proxy, this._notebookService));
		}
		return this._modelManager;
	}