Unable to use Converter with Avalonia

Question

I am unable to use a converter in XAML. I followed the documentation however it seems incorrect or outdated.

namespace Mazes.Ui.Temporary.Converters
{
    public class TimeSpanConverter : IValueConverter
    {
        public object? Convert(object? value, Type targetType, object? parameter, CultureInfo culture)
        {
           // ...
        }
    }
}

I register the converter in MainWindow where the window is declared.

<Window xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:vm="using:Mazes.Ui.Temporary.ViewModels"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:views="clr-namespace:Mazes.Ui.Temporary.Views"
        xmlns:local="clr-namespace:Mazes.Ui.Temporary.Converters;assembly=Mazes.Ui.Temporary"
        mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
        x:Class="Mazes.Ui.Temporary.Views.MainWindow"
        Icon="/Assets/avalonia-logo.ico"
        Title="Mazes.Ui.Temporary">
    <Window.Resources>
        <local:TimeSpanConverter x:Key="timeSpanConverter" />
    </Window.Resources>
    <views:MainView />
</Window>

I then try to use it in MainView where it is bound to a property in the view model.

<TextBlock Text="{CompiledBinding ComputeTime, Converter={StaticResource timeSpanConverter}}" Grid.Row="0" Grid.Column="1"/>

However I get the following error in both MainView and MainWindow: Static resource 'timespanConverter' not found.