PrintJob.setSourceFd

Make the [gtk.print_job.PrintJob] send an existing document to the printing system.

The file can be in any format understood by the platforms printing system (typically PostScript, but on many platforms PDF may work too). See [gtk.printer.Printer.acceptsPdf] and [gtk.printer.Printer.acceptsPs].

This is similar to [gtk.print_job.PrintJob.setSourceFile], but takes expects an open file descriptor for the file, instead of a filename.