private void createSnapshot(RegionStateNode node, Map<ServerName, List<RegionInfo>> result) {
    final ServerName serverName = node.getRegionLocation();
    if (serverName == null) {
      return;
    }

    List<RegionInfo> serverRegions = result.get(serverName);
    if (serverRegions == null) {
      serverRegions = new ArrayList<RegionInfo>();
      result.put(serverName, serverRegions);
    }
    serverRegions.add(node.getRegionInfo());
  }
Returns True if region is offline (In OFFLINE or CLOSED state).
hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/RegionStates.java