@Override
    public void addTimeChangeListener(TimestampGeneratorImpl.TimeChangeListener listener) {
        synchronized (this) {
            this.timeChangeListeners.add(listener);
        }
    }
Register to listen for time changes.

@param listener any listeners interested on time change.
@see Scheduler
modules/siddhi-core/src/main/java/io/siddhi/core/util/timestamp/TimestampGeneratorImpl.java