removeWithKey method
Implementation
void removeWithKey(String key, int? ts) {
final existData = _cachedDataMap[key];
final time = ts ?? DateTime.now().millisecondsSinceEpoch;
if (existData != null && existData.ts < time) {
existData
..isRemoved = true
..ts = time;
}
if (_cachedDataMap.isEmpty) (policy as PeriodEviction).stop();
}