in lib/src/usage_impl.dart [46:54]
void _checkReplenish() {
final now = DateTime.now().millisecondsSinceEpoch;
if (_lastReplenish + 1000 < now) {
final inc = (now - _lastReplenish) ~/ 1000;
drops = math.min(drops + inc, startingCount);
_lastReplenish += (1000 * inc);
}
}