Sample code for loading HiveList from storage

**Question**
How to retrieve HiveList ? How to open the box for HiveListImpl.box"

**Code sample**
```dart
static Future> getAllSaleTickets() async {

final _saleTicketBox = await Hive.box(_hive.SALE_TICKET_BOX);
final _saleTicketHeaderBox = await Hive.box(_hive.SALE_TICKET_COL_BOX);

final _saleTicketHeader = (_saleTicketBox.isEmpty || _saleTicketBox.values.isEmpty)
? SaleTicketHeader()
: _saleTicketHeaderBox.values.firstWhere((t) => t.id=1);

// _saleTicketHeader.saleTickets = HiveList(_saleTicketBox); // open ticket box but empty list
return _saleTicketHeader.saleTickets.toList();
}
```

**Version**
- Platform: iOS, Android, Mac, Windows, Linux, Web
- Flutter version: [e.g. 1.14.6]
- hive: ^1.4.0-dev3
- hive_flutter: ^0.3.0+1