presto-main/src/main/java/io/prestosql/failuredetector/HeartbeatFailureDetector.java/HeartbeatFailureDetector/isFailed
class HeartbeatFailureDetector:        public synchronized boolean isFailed()
        {
            return future == null || // are we disabled?
                    successTransitionTimestamp == null || // are we in success state?
                    Duration.nanosSince(successTransitionTimestamp).compareTo(warmupInterval) < 0; // are we within the warmup period?
        }