toJson method
Serialises to a JSON-compatible map. Omits null / empty fields.
Implementation
Map<String, dynamic> toJson() => {
if (osName != null) 'osName': osName,
if (osVersion != null) 'osVersion': osVersion,
if (deviceModel != null) 'deviceModel': deviceModel,
if (appName != null) 'appName': appName,
if (buildNumber != null) 'buildNumber': buildNumber,
if (extra.isNotEmpty) 'extra': extra,
};