com.unity.uiwidgets/com.unity.uiwidgets.devtools/Editor/listenable.cs

using Unity.UIWidgets.foundation;
using Unity.UIWidgets.ui;
using Unity.UIWidgets.widgets;

namespace Unity.UIWidgets.DevTools
{
    public class FixedValueListenable<T> : ValueListenable<T> {
        public FixedValueListenable(T _value)
        {
            this._value = _value;
        }

    public readonly T _value;
    
    public void addListener(VoidCallback listener){} //public override void addListener(VoidCallback listener){}
    
    public void removeListener(VoidCallback listener){} //public override void removeListener(VoidCallback listener){}

    public T value => _value; // public override T value => _value;
    }
}