build method
Implementation
@override
void build(PdfPage page, PdfObject object, PdfDict params) {
super.build(page, object, params);
if (alternateName != null) {
params['/TU'] = PdfString.fromString(alternateName!);
}
if (mappingName != null) {
params['/TM'] = PdfString.fromString(mappingName!);
}
params['/Ff'] = PdfNum(fieldFlagsValue);
}