read a pdf is error.

position：PdfSharpCore.Pdf.IO.Parser.ReadXRefTableAndTrailer(PdfCrossReferenceTable xrefTable)

        private PdfTrailer ReadXRefTableAndTrailer(PdfCrossReferenceTable xrefTable)
        {
            Debug.Assert(xrefTable != null);

            Symbol symbol = ScanNextToken();/// return  Keyword

read.PDF

    class Program
    {
        static void Main(string[] args)
        {
            var bytes = File.ReadAllBytes("read.PDF");
            using (var ms = new MemoryStream(bytes)) {
                var document = PdfReader.Open(ms);// throw error
            }
        }
    }