increment method
Increments the value of an item in the cache.
Implementation
@override
Future<int> increment(String key, [int value = 1]) async {
final cmd = await _getCommand();
if (value == 1) {
final res = await cmd.send_object(['INCR', key]);
return res is int ? res : int.parse(res.toString());
}
final res = await cmd.send_object(['INCRBY', key, value]);
return res is int ? res : int.parse(res.toString());
}