toJson method
Implementation
@override
Map<String, dynamic> toJson() => <String, dynamic>{
'gifter_user_id': gifterUserId,
'receiver_user_id': receiverUserId,
'currency': currency,
'amount': amount,
'cryptocurrency': cryptocurrency,
'cryptocurrency_amount': cryptocurrencyAmount.toString(),
'star_count': starCount,
'transaction_id': transactionId,
'sticker': sticker?.toJson(),
'@type': constructor,
};