delete method
Removes the given key from store.
staleOnly
flag will remove it only if the key is expired
(from maxStale).
Implementation
@override
Future<void> delete(String key, {bool staleOnly = false}) {
final resp = _cache.entries[key];
if (resp == null) return Future.value();
if (staleOnly && !resp.value.isStaled()) {
return Future.value();
}
_cache.remove(key);
return Future.value();
}