internal IEnumerator <T> GetEnumerator_Stub <T>()
        {
            IIterable <T> _this = JitHelpers.UnsafeCast <IIterable <T> >(this);

            return(new IteratorToEnumeratorAdapter <T>(_this.First()));
        }
        internal IEnumerator <T> GetEnumerator_Stub <T>()
        {
            IIterable <T> _this = Unsafe.As <IIterable <T> >(this);

            return(new IteratorToEnumeratorAdapter <T>(_this.First()));
        }