@Override
        public String toString() {
            return "Response{" +
                    "count=" + count +
                    ", totalLatencyMillis=" + totalLatencyMillis +
                    ", averageLatencyMillis=" + averageLatencyMillis +
                    ", minLatencyMillis=" + minLatencyMillis +
                    ", maxLatencyMillis=" + maxLatencyMillis +
                    ", bytesReceived=" + bytesReceived +
                    ", rate=" + rate +
                    '}';
        }
@see #operationAverageLatencyMillis()
@return max latency as milliseconds
vespa-feed-client-api/src/main/java/ai/vespa/feed/client/OperationStats.java