@Override
      public Object call() throws Exception {
        Region r = getCache().getRegion(regionName);
        r.registerInterest("ALL_KEYS");
        return null;
      }
Partitioned Region test for bug #42195: putIfAbsent from client does not put old value in local
cache
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/ConcurrentMapOpsDUnitTest.java