box.putAll(Map) triggering watch event Map.entries.length amount of time

**Question**
Is it possible for Hive to trigger BoxEvent only once when using putAll method? Now when adding map of entries to a box it gets triggered as many times as there are entries.

**Code sample**
using this code:
```dart
box.watch().map(
(BoxEvent _) {
print("watchAll: " + T.toString() + " " + _.toString());
return box.values.toList();
},
)
```
I'm getting this output:
```
I/flutter (14849): watchAll: Reward Instance of 'BoxEvent'
I/flutter (14849): watchAll: Reward Instance of 'BoxEvent'
I/flutter (14849): watchAll: Reward Instance of 'BoxEvent'
I/flutter (14849): watchAll: Reward Instance of 'BoxEvent'
I/flutter (14849): watchAll: Reward Instance of 'BoxEvent'
I/flutter (14849): watchAll: Reward Instance of 'BoxEvent'
I/flutter (14849): watchAll: Reward Instance of 'BoxEvent'
I/flutter (14849): watchAll: Reward Instance of 'BoxEvent'
```

**Version**
- Platform: iOS, Android, Web
- Flutter version: Flutter 3.0.3 • channel stable
- Hive version: 2.2.1
- Hive_flutter version: 1.1.0
- Hive_generator version: 1.1.3

Start with the Box.putAll and box.watch entry points described in the issue, then reproduce the sample using a multi-entry map on the listed Hive and Flutter versions. Done means one batch produces a single BoxEvent instead of one event per entry, with coverage for the observed behavior.

Written by the indexing model from the issue text.