@Override
  public boolean waitForCacheInitialization(long timeout) {
    return this.l1Cache.waitForCacheInitialization(timeout)
      && this.l2Cache.waitForCacheInitialization(timeout);
  }
Returns the list of fully cached files
hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/CombinedBlockCache.java