public ImmutableList<String> extractDocComment(Element element) {
    // Only extract for generated type which is public
    if (constitution.implementationVisibility().isPublic()) {
      @Nullable String docComment = constitution
          .protoclass()
          .processing()
          .getElementUtils()
          .getDocComment(CachingElements.getDelegate(element));

      if (docComment != null) {
        return ImmutableList.copyOf(DOC_COMMENT_LINE_SPLITTER.split(docComment));
      }
    }
    return ImmutableList.of();
  }
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