问IText7在.NET 5上抛出FileNotFoundException

EN

private byte[] BuildPDF()
{
   using(var stream = new MemoryStream())
   {
        PdfDocument pdfDoc = new PdfDocument(new PdfWriter(stream));
        Document doc = new Document(pdfDoc);

        Table table = new Table(UnitValue.CreatePercentArray(8)).UseAllAvailableWidth();

        for (int i = 0; i < 16; i++)
        {
           table.AddCell("hi");
        }

       doc.Add(table);

       doc.Close();
   
       return stream.ToArray();
   }
}

An unhandled exception occurred while processing the request.
FileNotFoundException: Could not load file or assembly 'Microsoft.DotNet.PlatformAbstractions,
Version=1.1.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60'. 
The system cannot find the file specified.

iText.IO.Util.ResourceUtil.LoadITextResourceAssemblies()

TypeInitializationException: The type initializer for 'iText.IO.Util.ResourceUtil' threw an exception.

iText.IO.Font.Type1Parser.GetMetricsFile()