class Program
    {
        static void Main(string[] args)
        {
            GlobalFontSettings.FontResolver = new FontResolver();

            var pdf = new PdfDocument();
            var page = pdf.AddPage();
            page.Orientation = PdfSharp.PageOrientation.Portrait;
            page.Size = PdfSharp.PageSize.Letter;

            using (var pdfDraw = XGraphics.FromPdfPage(page))
            {
                // I tried using this in the XFont c-tor and it didn't make any difference
                // var pdfFontOptions = new XPdfFontOptions(PdfFontEncoding.Unicode);

                var font = new XFont("Symbola", 12, XFontStyle.Regular);

                // Rendering this character does not work - I see two [?][?] boxes in the PDF.
                pdfDraw.DrawString(System.Net.WebUtility.HtmlDecode(" 🖳 "), font, XBrushes.Black, new XPoint(100, 200), StringFormats.BaseLineLeft);
                pdfDraw.DrawString("\U0001F5B3", font, XBrushes.Black, new XPoint(100, 300), XStringFormats.BaseLineLeft);

                // Rendering this character (< 0x10000) works as expected.
                pdfDraw.DrawString(System.Net.WebUtility.HtmlDecode(" &#9658;"), font, XBrushes.Black, new XPoint(200, 200), XStringFormats.BaseLineLeft);
                pdfDraw.DrawString("\U000025BA", font, XBrushes.Black, new XPoint(200, 300), XStringFormats.BaseLineLeft);

                pdf.Save("C:\\temp\\result.pdf");
            }
        }

        public class FontResolver : IFontResolver
        {
            public byte[] GetFont(string faceName)
            {
                if(faceName == "Symbola")
                {
                     return System.IO.File.ReadAllBytes("C:\\temp\\Symbola.ttf");
                }
                return null;
            }

            public FontResolverInfo ResolveTypeface(string familyName, bool isBold, bool isItalic)
            {
                if(familyName == "Symbola")
                {
                    return new FontResolverInfo("Symbola");
                }

                return PlatformFontResolver.ResolveTypeface(familyName, isBold, isItalic);
            }
        }
    }