@Override
    public synchronized void goingToFlush() {
      try {
        if (!cleared) {
          // once the flusher is stuck in our listener do a region clear
          region.clear();
          cleared = true;
        }
      } catch (AssertionError | Exception e) {
        errorCollector.addError(e);
      }
    }
Performs Region clear during DiskStore flush and then performs create after flushing.

<p>
TRAC #41770: ConcurrentRegionOperationsJUnitTest fails with duplicate create in an oplog
geode-core/src/integrationTest/java/org/apache/geode/internal/cache/DiskRegionJUnitTest.java