extensions/markdown-language-features/src/util/workspaceCache.ts/MdDocumentInfoCache/constructor
class MdDocumentInfoCache:	public constructor(
		private readonly workspace: IMdWorkspace,
		private readonly getValue: (document: ITextDocument) => Promise<T>,
	) {
		super();

		this._register(this.workspace.onDidChangeMarkdownDocument(doc => this.invalidate(doc)));
		this._register(this.workspace.onDidDeleteMarkdownDocument(this.onDidDeleteDocument, this));
	}