code: func (f *Fpdf) SetSubject(subjectStr string, isUTF8 bool) {
  	if isUTF8 {
  		subjectStr = utf8toutf16(subjectStr)
  	}
  	f.subject = subjectStr
  }
docs: // SetSubject defines the subject of the document. isUTF8 indicates if the
  // string is encoded in ISO-8859-1 (false) or UTF-8 (true).