src/vs/workbench/contrib/comments/browser/commentService.ts/CommentService/getNotebookComments
class CommentService:	async getNotebookComments(resource: URI): Promise<(INotebookCommentInfo | null)[]> {
		const commentControlResult: Promise<INotebookCommentInfo | null>[] = [];

		this._commentControls.forEach(control => {
			commentControlResult.push(control.getNotebookComments(resource, CancellationToken.None)
				.catch(_ => {
					return null;
				}));
		});

		return Promise.all(commentControlResult);
	}