RED,
    YELLOW,
    GREEN
  }

  private abstract static class CountingSupplier<E> implements Supplier<E>, Serializable {
    int count;

    abstract E getImpl();

    @Override
    public E get() {
      count++;
      return getImpl();
    }
  }

  private static class QueueSupplier extends CountingSupplier<Queue<Integer>> {
    @Override
    /*

      if (obj instanceof CountingSupplier) {
        return this.value == ((CountingSupplier) obj).value;
      }
      return false;
    }

    @Override
    public int hashCode() {
      return value;
    }
  }

  public void testForSupplier() {
    Supplier<Integer> supplier = new CountingSupplier();