public static RegionInfo loadRegionInfoFileContent(final FileSystem fs, final Path regionDir)
    throws IOException {
    FSDataInputStream in = fs.open(new Path(regionDir, REGION_INFO_FILE));
    try {
      return RegionInfo.parseFrom(in);
    } finally {
      in.close();
    }
  }
Create a {@link RegionInfo} from the serialized version on-disk.
@param fs        {@link FileSystem} that contains the Region Info file
@param regionDir {@link Path} to the Region Directory that contains the Info file
@return An {@link RegionInfo} instance gotten from the Region Info file.
@throws IOException if an error occurred during file open/read operation.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionFileSystem.java