code: long getRequestTimeoutMillisForCurrentAttempt() {
      RetryHelper.Context context = RetryHelper.getContext();
      if (context == null) {
        return getRequestTimeoutMillis();
      }
      int attempt = context.getAttemptNumber();
      return getExponentialValue(
          requestTimeoutMillis, requestTimeoutRetryFactor, maxRequestTimeout, attempt);
    }
docs: Returns a request-timeout in milliseconds for the current attempt.
  The returned value is based on the initial-value * back-off ^ (attempt -1)
  but bounded by the max-value. Identical to {@link #getRequestTimeoutMillis}
  if {@link RetryHelper.Context} is not available.