toJson method
Implementation
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = <String, dynamic>{};
data['id'] = id;
data['object'] = object;
data['created'] = created;
data['model'] = model;
data['usage'] = usage.toJson();
data['choices'] = choices.map((x) => x.toJson()).toList();
return data;
}