public override ILexer <HeaderField> Create()
        {
            var ows        = OptionalWhiteSpaceLexerFactory.Create();
            var innerLexer = Concatenation.Create(
                FieldNameLexerFactory.Create(),
                Terminal.Create(@":", StringComparer.Ordinal),
                ows,
                FieldValueLexerFactory.Create(),
                ows);

            return(new HeaderFieldLexer(innerLexer));
        }
        public override ILexer <Trailer> Create()
        {
            var innerLexer = RequiredDelimitedListLexerFactory.Create(FieldNameLexerFactory.Create());

            return(new TrailerLexer(innerLexer));
        }