@Override
        public Map<String, Object> snapshot() {
            HashMap<String, Object> state = new HashMap<>();
            state.put("lastTimestamp", this.lastTimestamp);
            return state;
        }
return true/false based on timestamp values

@param data  of Long type
@param state function state
@return true/false
modules/siddhi-core/src/main/java/io/siddhi/core/executor/incremental/IncrementalShouldUpdateFunctionExecutor.java