extensions/markdown-language-features/src/tableOfContents.ts/MdTableOfContentsProvider/constructor
class MdTableOfContentsProvider:	constructor(
		private readonly parser: IMdParser,
		workspace: IMdWorkspace,
		private readonly logger: ILogger,
	) {
		super();
		this._cache = this._register(new MdDocumentInfoCache<TableOfContents>(workspace, doc => {
			this.logger.verbose('TableOfContentsProvider', `create - ${doc.uri}`);
			return TableOfContents.create(parser, doc);
		}));
	}