default void notifyFileCachingCompleted(Path fileName, int totalBlockCount, int dataBlockCount,
    long size) {
    // noop
  }
Notifies the cache implementation that the given file has been fully cached (all its blocks
made into the cache).
@param fileName        the file that has been completely cached.
@param totalBlockCount the total of blocks cached for this file.
@param dataBlockCount  number of DATA block type cached.
@param size            the size, in bytes, cached.
hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/BlockCache.java