public NotificationManager(INotificationHandler[] handlers)
{
_handlers = handlers.Select(h => new
{
Handler = h,
Type = (HandleNotificationTypeAttribute)h.GetType().GetCustomAttributes(typeof(HandleNotificationTypeAttribute), false).FirstOrDefault(),
})
.Where(h => h.Type != null)
.ToLookup(h => h.Type.Type, h => h.Handler, StringComparer.OrdinalIgnoreCase);
}