public async Task <IActionResult> SaveByHtml()
        {
            var html = @"<!DOCTYPE html>
                        <html>
                        <head>
                        </head>
                        <body>
                            <header>
                                <h1>This is a hardcoded test</h1>
                            </header>
                            <div>
                                <h2>456789</h2>
                            </div>
                        </body>";

            var builder = new HtmlAsPdf();

            System.IO.File.WriteAllBytes("testHard.pdf", builder.GetPDF(html));
            return(Ok());
        }
        public async Task <IActionResult> GetByHtml()
        {
            var html = @"<!DOCTYPE html>
                        <html>
                        <head>
                        </head>
                        <body>
                            <header>
                                <h1>This is a hardcoded test</h1>
                            </header>
                            <div>
                                <h2>456789</h2>
                            </div>
                        </body>";

            var          builder   = new HtmlAsPdf();
            var          pdf       = builder.GetPDF(html);
            MemoryStream pdfStream = new MemoryStream();

            pdfStream.Write(pdf, 0, pdf.Length);
            pdfStream.Position = 0;
            return(new FileStreamResult(pdfStream, "application/pdf"));
        }