How can I add additional margin to an existing PDF when printing with the Flutter 'printing' package?

Question

I am trying to print a pdf with additional margin in windows from flutter with printing package with this code:

left_margin = 10
format = PdfPageFormat.roll57.applyMargin(left:left_margin, top:0, right:0, bottom:0);
await Printing.directPrintPdf(printer: selectedPrint, format: format, onLayout: (_) => pdf_file.buffer.asUint8List());

Prints, but I can put any value in left_margin than is always ignored.

How can I add a additional marging in a existing pdf?