@Override
    public boolean toStream() {
        return metaStreamEvents[0].getEventType() == MetaStreamEvent.EventType.DEFAULT ||
                metaStreamEvents[0].getEventType() == MetaStreamEvent.EventType.WINDOW;
    }
{StreamJunction.Receiver} implementation to receive events to be fed into multi
stream processors which consume multiple streams.
modules/siddhi-core/src/main/java/io/siddhi/core/query/input/MultiProcessStreamReceiver.java