private void preConvertPairFirsts(List<Pair> pairs, StoreKeyConverter storeKeyConverter) throws Exception {
    List<StoreKey> pairFirsts = new ArrayList<>();
    for (Pair<String, String> pair : pairs) {
      pairFirsts.add(createBlobId(pair.getFirst()));
    }
    storeKeyConverter.convert(pairFirsts);
  }
Runs all the {@link Pair#getFirst()} outputs from the {@link Pair} list through
the {@link StoreKeyConverter} storeKeyConverter.
Intended to be run so that the StoreKeyConverter's
{@link StoreKeyConverter#getConverted(StoreKey)} method can
work on any of the pairs' getFirst() outputs.
@param pairs
@param storeKeyConverter
@throws Exception {@link StoreKeyConverter#convert(Collection)} may throw an Exception
ambry-replication/src/test/java/com/github/ambry/replication/BlobIdTransformerTest.java