presto-main/src/main/java/io/prestosql/failuredetector/HeartbeatFailureDetector.java/HeartbeatFailureDetector/disable
class HeartbeatFailureDetector:        public synchronized void disable()
        {
            if (future != null) {
                future.cancel(true);
                future = null;
                disabledTimestamp = System.nanoTime();
            }
        }