private void clientPopulateServers() throws Exception {
    Properties properties2 = new Properties();
    properties2.setProperty("cache-xml-file", CLIENT_XML);
    ClientVM clientVM =
        clusterStartupRule.startClientVM(SERVER_ZONE_MAP.size() + 1, properties2,
            ccf -> ccf.addPoolLocator("localhost", locatorPort));

    clientVM.invoke(() -> {
      Map<Integer, String> putMap = new HashMap<>();
      for (int i = 0; i < 1000; i++) {
        putMap.put(i, "A");
      }

      ClientCache clientCache = ClusterStartupRule.getClientCache();

      Stream.of(REGION_NAME, COLOCATED_REGION_NAME).forEach(regionName -> {
        Region<Integer, String> region = clientCache.getRegion(regionName);
        region.putAll(putMap);
      });
    });
  }
Startup a client to put all the data in the server regions
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/control/RebalanceOperationComplexDistributedTest.java