code: public String getBatchName(G group, Batch<K, T> batch) {
      return "batch(keys: " + batch.keySize() + ", size: " + batch.batchSize() + ")";
    }
docs: Overriding this method allows providing custom name for a batch. Name will appear in the
  ParSeq trace as a description of the task that executes the batch.
  @param batch batch to be described
  @param group group to be described
  @return name for the batch and group