private SizeableGatewayEventSubstitutionFilter getSizeableGatewayEventSubstitutionFilter() {
    return (SizeableGatewayEventSubstitutionFilter) getGatewayEventSubstitutionFilter();
  }
Override as needed to add to the configuration, such as regionFactory.setOffHeap(boolean).
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/wan/asyncqueue/AsyncEventListenerWithFilterDistributedTest.java