How to render a vertical bar chart with Oxyplot

I'm using OxyPlot to render a bar chart with SkiaSharp. Currently, the bars are getting rendered horizontally, but i'd like them to be rendered vertically. I tried to swap the AxisPosition but this led to the following exception:

OxyPlot exception: BarSeries requires a CategoryAxis on the Y Axis.
An exception of type System.Exception was thrown when updating the plot model.
at OxyPlot.Series.BarSeriesBase`1.GetCategoryAxis()
at 
OxyPlot.Series.BarSeriesBase`1.OxyPlot.Series.IBarSeries.get_CategoryAxis()
at OxyPlot.PlotModel.<>c.<UpdateBarSeriesManagers>b__238_1(IBarSeries s)
at System.Linq.Lookup`2.Create(IEnumerable`1 source, Func`2 keySelector, 
IEqualityCom
at System.Linq.GroupedEnumerable`2.GetEnumerator()
at OxyPlot.PlotModel.UpdateBarSeriesManagers()
at OxyPlot.PlotModel.OxyPlot.IPlotModel.Update(Boolean updateData)

I'm currently using this example code snippet from the official repo:

var model = new PlotModel();

var categoryAxis = new CategoryAxis { Position = AxisPosition.Left };
var valueAxis1 = new LinearAxis
{
    Title = "Value Axis 1",
    Position = AxisPosition.Bottom,
    MinimumPadding = 0.06,
    MaximumPadding = 0.06,
    ExtraGridlines = new[] {0d},
    Key = "x1"
};
model.Axes.Add(categoryAxis);
model.Axes.Add(valueAxis1);

var series = new List<BarSeries>
{
    new BarSeries(),
    new BarSeries(),
};

var rnd = new Random(1);
foreach (var s in series)
{
    for (var i = 0; i < 4; i++)
        s.Items.Add(new BarItem() { Value = rnd.Next(0, 100) });
    model.Series.Add(s);
}

This is the rendered bar chart:

It looks like this was vertical bars were possible in the past using ColumnSeries, but this type of series has been removed. Does anyone know how this can be achieved?