@Override
      public boolean done() {
        Statistics si = getTenuredPoolStatistics(internalSystem.getStatisticsManager());
        if (si != null) {
          sampler.addLocalStatListener(l, si, "currentUsedMemory");
          return true;
        }
        return false;
      }
putting this test here because junit does not have host stat sampler enabled
geode-core/src/distributedTest/java/org/apache/geode/cache/management/MemoryThresholdsDUnitTest.java