public static HRegion openHRegion(final RegionInfo info, final TableDescriptor htd, final WAL wal,
    final Configuration conf) throws IOException {
    return openHRegion(info, htd, wal, conf, null, null);
  }
Open a Region.
@param info Info for region to be opened.
@param wal  WAL for region to use. This method will call WAL#setSequenceNumber(long) passing
            the result of the call to HRegion#getMinSequenceId() to ensure the wal id is
            properly kept up. HRegionStore does this every time it opens a new region.
@return new HRegion
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java