riversong-code-showcase/Source/Riversong/Game/UI/Panels/SpeedControlsPanel/SpeedControlsPanelModel.cs

using Unity.Properties;

namespace DanieleMarotta.RiversongCodeShowcase
{
    public class SpeedControlsPanelModel : UIModel
    {
        private int _speedLevel;

        [CreateProperty]
        public int SpeedLevel
        {
            get => _speedLevel;
            set => SetProperty(ref _speedLevel, value);
        }
    }
}