@Override
  public boolean evictBlock(BlockCacheKey cacheKey) {
    boolean l1Result = this.l1Cache.evictBlock(cacheKey);
    boolean l2Result = this.l2Cache.evictBlock(cacheKey);
    return l1Result || l2Result;
  }
@param cacheKey The block's cache key.
@param buf      The block contents wrapped in a ByteBuffer.
@param inMemory Whether block should be treated as in-memory. This parameter is only useful for
                the L1 lru cache.
hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/InclusiveCombinedBlockCache.java