public void clear() {
        this.operationChangeLog.clear();
        operationChangeLogSize = 0;
        forceFullSnapshot = true;

        previousToLastReturned = null;
        lastReturned = null;
        first = null;
        last = null;
        eventIndex = -1;
    }
Returns the next element in the iteration.

@return the next element in the iteration.
@throws NoSuchElementException iteration has no more elements.
modules/siddhi-core/src/main/java/io/siddhi/core/event/stream/holder/SnapshotableStreamEventQueue.java