src/vs/workbench/contrib/notebook/common/notebookEditorModel.ts/ComplexNotebookEditorModel/load
class ComplexNotebookEditorModel:	async load(options?: INotebookLoadOptions): Promise<IResolvedNotebookEditorModel> {
		if (options?.forceReadFromFile) {
			this._logService.debug('[notebook editor model] load from provider (forceRead)', this.resource.toString());
			this._loadFromProvider(undefined);
			assertType(this.isResolved());
			return this;
		}

		if (this.isResolved()) {
			return this;
		}

		let backup: IResolvedWorkingCopyBackup<NotebookDocumentBackupData> | undefined = undefined;

		try {
			backup = await this._workingCopyBackupService.resolve<NotebookDocumentBackupData>(this._workingCopyIdentifier);
		} catch (_e) { }

		if (this.isResolved()) {
			return this; // Make sure meanwhile someone else did not succeed in loading
		}

		this._logService.debug('[notebook editor model] load from provider', this.resource.toString());
		await this._loadFromProvider(backup);
		assertType(this.isResolved());
		return this;
	}