Umbraco-CMS/src/Umbraco.Core/Events/NotificationExtensions.cs

using System.Collections.Generic;

namespace Umbraco.Cms.Core.Events
{
    public static class NotificationExtensions
    {
        public static T WithState<T>(this T notification, IDictionary<string, object> state) where T : IStatefulNotification
        {
            notification.State = state;
            return notification;
        }

        public static T WithStateFrom<T, TSource>(this T notification, TSource source)
            where T : IStatefulNotification where TSource : IStatefulNotification
            => notification.WithState(source.State);
    }
}