toJson method
Implementation
core.Map<core.String, core.dynamic> toJson() => {
if (amountDisplayString != null)
'amountDisplayString': amountDisplayString!,
if (amountMicros != null) 'amountMicros': amountMicros!,
if (currency != null) 'currency': currency!,
if (userComment != null) 'userComment': userComment!,
};