toJson method
转换为JSON
Implementation
@override
Map<String, dynamic> toJson() => {
'eventId': eventId,
'timestamp': timestamp.millisecondsSinceEpoch,
'type': type.toString(),
'sessionId': sessionId,
'eventName': eventName,
'systemInfo': systemInfo,
'level': level,
'source': source,
'metadata': metadata,
};