Flutter when serializing list of objects with jsonEncode the final string is getting cutt off - flutter

Question

I have difficulty to convert a long list to JSON string. This is my main model which I want to convert to JSON string
class ActivityBookingRequest {
int adminId;
List<ActivityBookingDetail> activityBookingList;
Map toJson() {
List<Map> activityBookingListMap = this.activityBookingList != null
? this.activityBookingList.map((i) => i.toJson()).toList()
: null;
return {
'adminId': adminId,
'activityBookList': activityBookingListMap,
};
}
}
This is my sub-model which is the list I am trying to serialize!
class ActivityBookingDetail {
int bookingId;
int resourceId;
int sourceId;
String sourceName;
int productId;
String pickupDate;
String cutOffDate;
int adultNumber;
int childrenNumber;
ActivityBookingDetail(
this.bookingId,
this.resourceId,
this.sourceId,
this.sourceName,
this.productId,
this.pickupDate,
this.cutOffDate,
this.adultNumber,
this.childrenNumber,
);
Map<String, dynamic> toJson() {
return {
'ssId': bookingId,
'ssResourceId': resourceId,
'sourceId': sourceId,
'sourceName': sourceName,
'productId': productId,
'pickupDate': pickupDate,
'cutOffDate': cutOffDate,
'noAdult': adultNumber,
'noChild': childrenNumber,
};
}
}
When I convert this to a JSON string if the list is long, the final JSON string is getting cut off!
{"adminId":213,{"ssId":4,"ssResourceId":4,"sourceId":1,"sourceName":"TRES","productId":3,"pickupDate":"2022-09-08T18:30:00","cutOffDate":"2022-09-08T18:30:00","noAdult":1,"noChi