static long calculateFailedRequestDelay(int failures, TimingValues timingValues) {
        long delay = timingValues.getFixedDelay() * (long)Math.pow(2, failures);
        delay = Math.max(timingValues.getFixedDelay(), Math.min(60_000, delay)); // between timingValues.getFixedDelay() and 60 seconds
        delay = timingValues.getPlusMinusFractionRandom(delay, randomFraction);

        return delay;
    }
Requests the config for the {@link com.yahoo.config.ConfigInstance} on the given {@link ConfigSubscription}

@param sub a subscription
config/src/main/java/com/yahoo/config/subscription/impl/JRTConfigRequester.java