private String createRepartitionSource(final String repartitionTopicNamePrefix,
                                           final OptimizableRepartitionNodeBuilder<K, V> optimizableRepartitionNodeBuilder) {

        return KStreamImpl.createRepartitionedSource(builder,
                                                     keySerde,
                                                     valueSerde,
                                                     repartitionTopicNamePrefix,
                                                     null,
                                                     optimizableRepartitionNodeBuilder);

    }
@return the new sourceName of the repartitioned source
streams/src/main/java/org/apache/kafka/streams/kstream/internals/GroupedStreamAggregateBuilder.java