How do I show PDF annotations when rendering using PdfiumViewer?

Question

I cannot get PDF annotations to appear using pdfium viewer, but they show when using adobe. I am loading the image returned from this function into a picture box.

Furthermore, I have the following annotations on a PDF: text, shape, line.

internal static List<byte[]> GetTiffByteArrayFromPDF(string filePath, int DpiPdfX = 300, int DpiPdfY = 300)
{
    List<byte[]> pdfPages = new List<byte[]>();
    try
    {
        using (var pdfDocument = PdfDocument.Load(filePath))
        {
            for (int i = 0; i < pdfDocument.PageCount; i++)
            {
                using (MemoryStream memoryStream = new MemoryStream())
                {
                    var pdfImage = pdfDocument.Render(i, DpiPdfX, DpiPdfY, PdfRenderFlags.CorrectFromDpi);
                    pdfImage.Save(memoryStream, ImageFormat.Tiff);
                    pdfPages.Add(memoryStream.ToArray());
                }
            }
        }
    }
    catch (Exception e)
    {
        Log.Error(e.ToString());
        Log.Error("GetTiffByteArrayFromPDF Error: " + e.Message);
        Log.Error("Details: ");
        Log.Error(e.ToString());
    }

    return pdfPages;
}

I have tried using PdfRenderFlags.Annotations alone and bitwise OR combined with PdfRenderFlags.CorrectFromDpi like PdfRenderFlags.CorrectFromDpi|PdfRenderFlags.Annotations.