void ICollection <TElement> .Clear() { throw Error.NotSupported(); }
void ICollection <TElement> .Add(TElement item) { throw Error.NotSupported(); }
void IList <TElement> .RemoveAt(int index) { throw Error.NotSupported(); }
void IList <TElement> .Insert(int index, TElement item) { throw Error.NotSupported(); }
bool ICollection <TElement> .Remove(TElement item) { throw Error.NotSupported(); }
void IEnumerator.Reset() { throw Error.NotSupported(); }