readXmp method
Document XMP (/Metadata), as text, when there is any.
Implementation
String? readXmp() {
final value = _catalog[PdfNameTokens.metadata];
if (value == null) return null;
final parser = document.prev;
if (parser is PdfDocumentParser && value is PdfIndirectLike) {
final data = _streamOf(parser, value);
if (data != null) return utf8.decode(data, allowMalformed: true);
}
return null;
}