@Override
    public StreamEvent find(StateEvent matchingEvent, Object storeEvents, StreamEventCloner storeEventCloner) {
        SnapshotableStreamEventQueue storeEventQueue = (SnapshotableStreamEventQueue) storeEvents;
        ComplexEventChunk<StreamEvent> returnEventChunk = new ComplexEventChunk<>();

        storeEventQueue.reset();
        while (storeEventQueue.hasNext()) {
            StreamEvent storeEvent = storeEventQueue.next();
            matchingEvent.setEvent(storeEventPosition, storeEvent);
            if ((Boolean) expressionExecutor.execute(matchingEvent)) {
                returnEventChunk.add(storeEventCloner.copyStreamEvent(storeEvent));
            }
            matchingEvent.setEvent(storeEventPosition, null);
        }
        return returnEventChunk.getFirst();

    }
Operator which is related to non-indexed In-memory table operations.
modules/siddhi-core/src/main/java/io/siddhi/core/util/collection/operator/SnapshotableEventQueueOperator.java