presto-main/src/main/java/io/prestosql/server/remotetask/ContinuousTaskStatusFetcher.java/ContinuousTaskStatusFetcher/addStateChangeListener
class ContinuousTaskStatusFetcher:    public void addStateChangeListener(StateMachine.StateChangeListener<TaskStatus> stateChangeListener)
    {
        taskStatus.addStateChangeListener(stateChangeListener);
    }