docs: private void failOnOverlapOfClearedPropagated() {
          HashSet<String> overlap = new HashSet<String>(cleared);
          overlap.retainAll(propagated);
          if (overlap.isEmpty()) // only possible if builder is concurrently modified during build
              throw new ConcurrentModificationException();
          throw new IllegalStateException(Tr.formatMessage(tc, "CWWKC1151.context.lists.overlap", overlap));
      }