src/vs/workbench/api/browser/mainThreadComments.ts/MainThreadCommentController/getNotebookComments
class MainThreadCommentController:	async getNotebookComments(resource: URI, token: CancellationToken) {
		if (resource.scheme !== Schemas.vscodeNotebookCell) {
			return <INotebookCommentInfo>{
				owner: this._uniqueId,
				label: this.label,
				threads: []
			};
		}

		let ret: languages.CommentThread<IRange | ICellRange>[] = [];
		for (let thread of [...this._threads.keys()]) {
			const commentThread = this._threads.get(thread)!;
			if (commentThread.resource === resource.toString()) {
				ret.push(commentThread);
			}
		}

		return <INotebookCommentInfo>{
			owner: this._uniqueId,
			label: this.label,
			threads: ret
		};
	}