static void registerK1AndK2() {
    Region r = cache.getRegion(SEPARATOR + REGION_NAME);
    assertThat(r).isNotNull();
    List<String> list = new ArrayList<>();
    list.add(k1);
    list.add(k2);
    r.registerInterest(list, InterestResultPolicy.KEYS_VALUES);
  }
@param connectedServers is the expected number of connected servers (1 or more)
@param redundantServers is the expected number of redundant servers (0 or more)
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/tier/sockets/RedundancyLevelTestBase.java