get method
Implementation
Future<Uint8List?> get(String key) async {
// L1 SIEVE
final memHit = _sieveGet(key);
if (memHit != null) return memHit;
// L2 disk
final diskHit = await _diskGet(key);
if (diskHit != null && diskHit.isNotEmpty) {
_sievePut(key, diskHit);
return diskHit;
}
return null;
}