@Override
        public void afterSettingDiskRef() {
          Thread clearTh = new Thread(() -> region.clear());
          clearTh.start();
          try {
            ThreadUtils.join(clearTh, 120 * 1000);
            failure = clearTh.isAlive();
            failureCause = "Clear Thread still running !";
          } catch (Exception e) {
            failure = true;
            failureCause = e.toString();
          }
        }
Tests the condition when a 'put' on an alreay created entry and concurrent 'clear' are
happening. Thus if after HTree ref was set (in 'put'), the region got cleared (and same key
re-'put'), the entry will actually become a create in the VM The new Oplog should record it as
a create even though the Htree ref in ThreadLocal will not match with the current Htree Ref.
But the operation is valid & should get recorded in Oplog
geode-core/src/integrationTest/java/org/apache/geode/internal/cache/OplogJUnitTest.java