@Override
        public Duration getDelay(int executionCount) {
            Duration nextDelay = startDelay;
            for (int i = 1; i < executionCount; ++i) {
                nextDelay = nextDelay.multipliedBy(2);
            }
            return maxDelay.compareTo(nextDelay) > 0 ? nextDelay : maxDelay;
        }
An abstraction that calculates the next delay based on the current retry count.

@author bjorncs
http-utils/src/main/java/ai/vespa/util/http/hc4/retry/DelaySupplier.java