/// <summary>
 /// To create a Reactive Extension for the event of candles occurrence, change and end.
 /// </summary>
 /// <param name="candleManager">The candles manager.</param>
 /// <param name="series">Candles series to be traced for candles.</param>
 /// <returns>Reactive Extension.</returns>
 public static IObservable <Candle> RxWhenCandles(this ICandleManager candleManager, CandleSeries series)
 {
     if (series == null)
     {
         throw new ArgumentNullException(nameof(series));
     }
     return(candleManager.RxWhenCandlesChanged(series));
 }