toJson method

Implementation

Map<String, dynamic> toJson() {
  Map<String, dynamic> map = {
    "messageId": messageId,
    "timestamp": timestamp,
    "sign": sign,
    "language": language,
    "signVersion": signVersion,
    "payLoadVersion": payLoadVersion,
    "accessToken": accessToken,
    "file": file,
    "payload": payload?.toJson(),
  };
  map.removeWhere((key, value) => value == null);
  return map;
}