protected final List<Call<I>> cloneCalls() {
    int length = delegate.size();
    List<Call<I>> result = new ArrayList<>(length);
    for (Call<I> iCall : delegate) {
      result.add(iCall.clone());
    }
    return result;
  }
Customizes the aggregated result. For example, summarizing or making immutable.
zipkin/src/main/java/zipkin2/internal/AggregateCall.java