private void deleteFromIndexes(StreamEvent toDeleteEvent) {
        if (indexMetaData != null) {
            for (Map.Entry<String, Integer> indexEntry : indexMetaData.entrySet()) {
                TreeMap<Object, Set<StreamEvent>> indexMap = indexData.get(indexEntry.getKey());
                Object key = toDeleteEvent.getOutputData()[indexEntry.getValue()];
                Set<StreamEvent> values = indexMap.get(key);
                if (values != null) {
                    values.remove(toDeleteEvent);
                    if (values.size() == 0) {
                        indexMap.remove(key);
                    }
                }
            }
        }
    }
EventHolder implementation where events will be indexed and stored. This will offer faster access compared to
other EventHolder implementations. User can only add unique events based on a given primary key.
modules/siddhi-core/src/main/java/io/siddhi/core/table/holder/IndexEventHolder.java