@Override
  public final void preTearDown() throws Exception {
    vm0.invoke(HAGIIBugDUnitTest::closeCache);
    vm1.invoke(HAGIIBugDUnitTest::closeCache);
    vm2.invoke(HAGIIBugDUnitTest::closeCache);
    vm3.invoke(HAGIIBugDUnitTest::closeCache);
    cache = null;
    Invoke.invokeInEveryVM(new SerializableRunnable() {
      @Override
      public void run() {
        cache = null;
      }
    });
  }
This function creates regionqueue on 4 VMs
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/ha/HAGIIBugDUnitTest.java