CacheEvictionStats clearRegionBlockCache(Region region) {
    long evictedBlocks = 0;

    for (Store store : region.getStores()) {
      for (StoreFile hFile : store.getStorefiles()) {
        evictedBlocks += blockCache.evictBlocksByHfileName(hFile.getPath().getName());
      }
    }

    return CacheEvictionStats.builder().withEvictedBlocks(evictedBlocks).build();
  }
May be null if this is a master which not carry table.
@return The cache for mob files used by the regionserver.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java