custom_IEnumerator.cs

  class MyObjectEnumerator : IEnumerator<MyObject>
  {
      public bool MoveNext()
      {
          throw new NotImplementedException();
      }

      public void Reset()
      {
          throw new NotImplementedException();
      }

      public MyObject Current { get; }

      object IEnumerator.Current => Current;

      public void Dispose()
      {
          throw new NotImplementedException();
      }
  }