@Override
  protected StoreKey getConvertedKey(StoreKey storeKey, boolean isKeyPresent, StoreKey cachedMapping) {
    return cachedMapping;
  }
Add invalid mappings.
@param invalids the keys for which no mapping will be generated during conversion.
ambry-messageformat/src/test/java/com/github/ambry/messageformat/MessageSievingInputStreamTest.java