extensions/markdown-language-features/src/util/workspaceCache.ts/MdDocumentInfoCache/get
class MdDocumentInfoCache:	public async get(resource: vscode.Uri): Promise<T | undefined> {
		let existing = this._cache.get(resource);
		if (existing) {
			return existing;
		}

		const doc = await this.loadDocument(resource);
		if (!doc) {
			return undefined;
		}

		// Check if we have invalidated
		existing = this._cache.get(resource);
		if (existing) {
			return existing;
		}

		return this.resetEntry(doc)?.value;
	}