toJson method
Implementation
core.Map<core.String, core.dynamic> toJson() => {
if (attributes != null) 'attributes': attributes!,
if (data != null) 'data': data!,
if (messageId != null) 'messageId': messageId!,
if (orderingKey != null) 'orderingKey': orderingKey!,
if (publishTime != null) 'publishTime': publishTime!,
};