contains method
Checks if the cache contains an entry for the given key
.
Implementation
@override
Future<bool> contains(String key) async {
final cache = await getApplicationCacheDirectory();
final filePathBytes = utf8.encode(key);
final filePath = sha256.convert(filePathBytes).toString();
final file = File('${cache.path}/cross_cache/$filePath');
return file.exists();
}