@Override
        public Map<String, Object> snapshot() {
            Map<String, Object> state = new HashMap<>();
            state.put("NextEmitTime", nextEmitTime);
            state.put("StartTimeOfAggregates", startTimeOfAggregates);
            state.put("TimerStarted", timerStarted);
            return state;
        }
Incremental Executor implementation class for Persisted Aggregation
modules/siddhi-core/src/main/java/io/siddhi/core/aggregation/persistedaggregation/PersistedIncrementalExecutor.java