private Set<BlockCacheKey> getAllCacheKeysForFile(String hfileName, long init, long end) {
    return blocksByHFile.subSet(new BlockCacheKey(hfileName, init), true,
      new BlockCacheKey(hfileName, end), true);
  }
Evicts all blocks for a specific HFile.
<p>
This is used for evict-on-close to remove all blocks of a specific HFile.
@return the number of blocks evicted
hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/bucket/BucketCache.java