toString method
A string representation of this object.
Some classes have a default textual representation,
often paired with a static parse function (like int.parse).
These classes will provide the textual representation as
their string representation.
Other classes have no meaningful textual representation
that a program will care about.
Such classes will typically override toString to provide
useful information when inspecting the object,
mainly for debugging or logging.
Implementation
@override
String toString() {
  final $buf = StringBuffer()
    ..writeln('IssuingCardholderIndividualCardIssuingUserTermsAcceptance(');
  if (date != null) {
    $buf
      ..writeln()
      ..write('  date: ')
      ..write(date)
      ..write(',');
  }
  if (ip != null) {
    $buf
      ..writeln()
      ..write('  ip: ')
      ..write(ip)
      ..write(',');
  }
  if (userAgent != null) {
    $buf
      ..writeln()
      ..write('  user_agent: ')
      ..write(userAgent)
      ..write(',');
  }
  $buf.write(')');
  return $buf.toString();
}