/// <inheritdoc/>
protected override void Start()
{
ClearBitmaps();
base.Start();
pdfWriter = new PdfWriter(Stream);
pdfWriter.Begin();
PdfCatalog catalog = new PdfCatalog();
pdfPages = new PdfPages();
pdfPagesLink = pdfWriter.Prepare(pdfPages);
catalog.Pages = pdfPagesLink;
pdfWriter.Prepare(catalog);
hashList = new Dictionary <string, PdfIndirectObject>();
}