public AlphaVantage(string apiKey)
        {
            _config = new AlphaVantageConfig {
                ApiKey = apiKey
            };
            _service = new Lazy <IAlphaVantageService>(() => _config.Service ?? new AlphaVantageService(_config));

            Stocks     = new StockBuilders(() => _service.Value);
            Fx         = new FxBuilders(() => _service.Value);
            Cryptos    = new CryptoBuilders(() => _service.Value);
            Technicals = new TechnicalBuilders(() => _service.Value);
        }
 public AlphaVantageService(AlphaVantageConfig config)
 {
     _config = config;
 }