protected boolean shouldReplaceExistingCacheBlock(BlockCacheKey cacheKey, Cacheable newBlock) {
    return BlockCacheUtil.shouldReplaceExistingCacheBlock(this, cacheKey, newBlock);
  }
Cache the block to ramCache
@param cacheKey   block's cache key
@param cachedItem block buffer
@param inMemory   if block is in-memory
@param wait       if true, blocking wait when queue is full
hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/bucket/BucketCache.java