public Set<ValueAttribute> computeConstructorArguments() {
    return ImmutableSet.copyOf(
        FluentIterable.from(getSettableAttributes())
            .filter(Predicates.compose(Predicates.not(Predicates.equalTo(-1)), ToConstructorArgumentOrder.FUNCTION))
            .toSortedList(Ordering.natural().onResultOf(ToConstructorArgumentOrder.FUNCTION)));
  }
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