public static void doPuts(Integer num) {
    Region r = cache.getRegion(REGION_NAME);
    for (int i = 0; i < num; i++) {
      r.put("SAMPLE_" + i, "SAMPLE_" + i);
    }
  }
Simulates old value null, entry null
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/DeltaPropagationStatsDUnitTest.java