toJson method
Implementation
core.Map<core.String, core.dynamic> toJson() => {
if (cloudPubsubTopic != null) 'cloudPubsubTopic': cloudPubsubTopic!,
if (expiryTime != null) 'expiryTime': expiryTime!,
if (feed != null) 'feed': feed!,
if (registrationId != null) 'registrationId': registrationId!,
};