@Override
  public Map<StoreKey, StoreKey> convert(Collection<? extends StoreKey> input) throws Exception {
    Map<StoreKey, StoreKey> output = new HashMap<>();
    if (input != null) {
      input.forEach((storeKey) -> output.put(storeKey, storeKey));
    }
    return output;
  }
No-op StoreKeyConverter. StoreKeys get paired with themselves
ambry-commons/src/main/java/com/github/ambry/store/StoreKeyConverterImplNoOp.java