ImmutableLongArray iia = builder.build();
      for (int j = 0; j < iia.length(); j++) {
        assertThat(iia.get(j)).isEqualTo((long) j);
      }
    }
  }

  private enum BuilderOp {
    ADD_ONE {
      @Override
      void doIt(ImmutableLongArray.Builder builder, AtomicLong counter) {
        builder.add(counter.getAndIncrement());
      }
    },
    ADD_ARRAY {
      @Override