src/vs/workbench/api/common/extHostLanguageFeatures.ts/LinkProviderAdapter/resolveLink
class LinkProviderAdapter:	async resolveLink(id: extHostProtocol.ChainedCacheId, token: CancellationToken): Promise<extHostProtocol.ILinkDto | undefined> {
		if (typeof this._provider.resolveDocumentLink !== 'function') {
			return undefined;
		}
		const item = this._cache.get(...id);
		if (!item) {
			return undefined;
		}
		const link = await asPromise(() => this._provider.resolveDocumentLink!(item, token));
		if (!link || !LinkProviderAdapter._validateLink(link)) {
			return undefined;
		}
		return typeConvert.DocumentLink.from(link);
	}