code: func (c customRetryer) RetryRules(r *request.Request) time.Duration {
  	retryCount := r.RetryCount
  	if retryCount > 7 {
  		retryCount = 7
  	}
  
  	delay := (1 << uint(retryCount)) * (rand.Intn(50) + 200)
  	return time.Duration(delay) * time.Millisecond
  }
docs: // RetryRules overwrites the DefaultRetryer's method.
  // It uses a basic exponential backoff algorithm that returns an initial
  // delay of ~400ms with an upper limit of ~30 seconds which should prevent
  // causing a high number of consecutive throttling errors.
  // For reference: Route 53 enforces an account-wide(!) 5req/s query limit.