code: @Override
    public RetryPolicy withBackoff(Duration interval, Duration maxInterval) {
      return super.withBackoff(interval, maxInterval);
    }
docs: Sets the {@code interval} to pause for between attempts, exponentially backing of to the
  {@code maxInterval} multiplying successive intervals by a factor of 2.
  
  @throws NullPointerException if {@code interval} or {@code maxInterval} are null
  @throws IllegalArgumentException if {@code interval} is <= 0 or {@code interval} is >=
  {@code maxInterval}