@Override
  public List<WAL> getWALs() {
    return Collections.singletonList(log);
  }
@param factory    factory that made us, identity used for FS layout. may not be null
@param conf       may not be null
@param providerId differentiate between providers from one facotry, used for FS layout. may be
                  null
hbase-server/src/test/java/org/apache/hadoop/hbase/wal/IOTestProvider.java