conversation method
Implementation
Future<Iterable<Chat>> conversation(String contactId,
{DateTime? before, int? take}) async {
final Map<String, dynamic> queryParameters = {};
if (before != null) queryParameters['before'] = before.toIso8601String();
final response =
await dio.get('/chat/$contactId', queryParameters: queryParameters);
return (response.data as List).map((e) => Chat.fromJson(e));
}