Garbled characters when Japanese is used for signature information

[heoquay70]

Describe the bug and the expected behaviour
pdflibAddPlaceholder.ts
If Japanese is used for signature information,
When the signature information screen is opened with PDF software or a browser,

• @Property {string} reason
• @Property {string} contactInfo
• @Property {string} name
• @Property {string} location
  are garbled.

Is it a bug in signing or in the helpers?
placeholder-pdf-lib
pdflibAddPlaceholder.js

To Reproduce
How about modifying the following part?

  const signatureDict = doc.context.obj({
    Type: 'Sig',
    Filter: 'Adobe.PPKLite',
    SubFilter: subFilter,
    ByteRange: byteRange,
    Contents: placeholder,
    Reason: _pdfLib.PDFString.of(reason), ---> Reason: _pdfLib.PDFHexString.fromText(reason),
    M: _pdfLib.PDFString.fromDate(signingTime !== null && signingTime !== void 0 ? signingTime : new Date()),
    ContactInfo: _pdfLib.PDFString.of(contactInfo), ---> ContactInfo: _pdfLib.PDFHexString.fromText(contactInfo),
    Name: _pdfLib.PDFString.of(name), ---> Name: _pdfLib.PDFHexString.fromText(name),
    Location: _pdfLib.PDFString.of(location), ---> Location: _pdfLib.PDFHexString.fromText(location),
    Prop_Build: {
      Filter: {
        Name: 'Adobe.PPKLite'
      },
      ...appBuild
    }
  });

[vbuch]

Probably makes sense. That's where the source is https://github.com/vbuch/node-signpdf/blob/develop/packages/placeholder-pdf-lib/src/pdflibAddPlaceholder.js#L101