@Override
  public Optional<Boolean> blockFitsIntoTheCache(HFileBlock block) {
    if (isMetaBlock(block.getBlockType())) {
      return l1Cache.blockFitsIntoTheCache(block);
    } else {
      return l2Cache.blockFitsIntoTheCache(block);
    }
  }
Returns the list of fully cached files
hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/CombinedBlockCache.java