public List<ValueAttribute> getConstructorExcluded() {
    if (constructorExcluded == null) {
      constructorExcluded = FluentIterable.from(getSettableAttributes())
          .filter(Predicates.not(Predicates.in(getConstructorArguments())))
          .toList();
    }
    return constructorExcluded;
  }
Means object hashcode is cached at some point. Either lazily (on first access)
or eagerly (during construction).
@see #isUseLazyhash()
@see #isUsePrehashed()
value-processor/src/org/immutables/value/processor/meta/ValueType.java