public static Parser <TToken, IEnumerable <T> > EndBy1 <TToken, T>(
            this Parser <TToken, T> parser,
            Parser <TToken, Unit> sep)
        {
            /*
             * return InternalCombinator.EndBy1(parser, sep)
             *     .Select(delayedSeq => delayedSeq.AsEnumerable());
             */

            return(InternalCombinator.EndBy1_Optimized(parser, sep));
        }