@Override
    public Cacheable getBlock(BlockCacheKey key, boolean caching, boolean repeat,
      boolean updateCacheMetrics) {
      if (Thread.currentThread().getName().equals(GET_BLOCK_THREAD_NAME)) {
        /**
         * Wait for second getCyclicBarrier.await in {@link MyBucketCache2#removeFromRamCache} after
         * {@link BucketCache#removeFromRamCache}.
         */
        try {
          getCyclicBarrier.await();
        } catch (Throwable e) {
          throw new RuntimeException(e);
        }
      }
      Cacheable result = super.getBlock(key, caching, repeat, updateCacheMetrics);
      return result;
    }
Caching Block completed,release {@link #GET_BLOCK_THREAD_NAME} and
{@link #EVICT_BLOCK_THREAD_NAME}.
hbase-server/src/test/java/org/apache/hadoop/hbase/io/hfile/bucket/TestBucketCacheRefCnt.java