toJson method
Implementation
Map<String, dynamic> toJson() => {
'contents': contents != null ? base64.encode(contents!) : null,
'previous': previous != null ? base64.encode(previous!) : null,
'created': created?.millisecondsSinceEpoch,
'synced': synced?.millisecondsSinceEpoch,
'signature': signature != null ? base64.encode(signature!) : null,
};