@Override
    boolean testHook_forceExpiredTombstoneGC(int count, long timeout, TimeUnit unit)
        throws InterruptedException {
      // sync on blockGCLock since expireBatch syncs on it
      synchronized (getBlockGCLock()) {
        testHook_forceBatchExpireCall = new CountDownLatch(1);
      }
      try {
        synchronized (this) {
          testHook_forceExpirationCount += count;
          notifyAll();
        }
        return testHook_forceBatchExpireCall.await(timeout, unit);
      } finally {
        testHook_forceBatchExpireCall = null;
      }
    }
Returns true if keys needs to be tracked for clients registering interests on PR.
geode-core/src/main/java/org/apache/geode/internal/cache/TombstoneService.java