List<AnnotationInjection> getDeclaringPackageAnnotationInjections() {
    return constitution.protoclass().packageOf().getAnnotationInjections();
  }
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