class Player : ICustomObserverable
    {
        public int Health { get; private set; }
        Writer writer;

        // Register observer
        public void Subscribe(ICustomObvserver observer)
        {
            throw new NotImplementedException();
        }

        public void ApplyDamage(int damage)
        {
            Health -= damage;

        }

        public void NotifyObservers()
        {
            writer.Notify();
        }


    }