private void computeIfPersistentBucketCache(Consumer<BucketCache> computation) {
    if (blockCache instanceof CombinedBlockCache) {
      BlockCache l2 = ((CombinedBlockCache) blockCache).getSecondLevelCache();
      if (l2 instanceof BucketCache && ((BucketCache) l2).isCachePersistent()) {
        computation.accept((BucketCache) l2);
      }
    }
  }
Run init. Sets up wal and starts up all server threads.
@param c Extra configuration.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java