presto-main/src/main/java/io/prestosql/failuredetector/HeartbeatFailureDetector.java/HeartbeatFailureDetector/MonitoringTask
class HeartbeatFailureDetector:        private MonitoringTask(ServiceDescriptor service, URI uri)
        {
            this.uri = uri;
            this.service = service;
            this.stats = new Stats(uri);
        }