private async Task <IMultiPage <IBar> > getHistoricalBarsAsync(
     HistoricalCryptoBarsRequest request,
     CancellationToken cancellationToken = default) =>
 await _httpClient.GetAsync <IMultiPage <IBar>, JsonMultiBarsPage>(
     await request.EnsureNotNull(nameof(request)).Validate()
     .GetUriBuilderAsync(_httpClient).ConfigureAwait(false),
     cancellationToken).ConfigureAwait(false);
 public Task <IMultiPage <IBar> > GetHistoricalBarsAsync(
     HistoricalCryptoBarsRequest request,
     CancellationToken cancellationToken = default) =>
 request.Symbols.Count == 1
         ? listHistoricalBarsAsync(request, cancellationToken).AsMultiPageAsync <IBar, JsonMultiBarsPage>()
         : getHistoricalBarsAsync(request, cancellationToken);