public boolean isRegionInServerManagerStates(final RegionInfo hri) {
    final byte[] encodedName = hri.getEncodedNameAsBytes();
    return (storeFlushedSequenceIdsByRegion.containsKey(encodedName)
      || flushedSequenceIdByRegion.containsKey(encodedName));
  }
Called by delete table and similar to notify the ServerManager that a region was removed.
hbase-server/src/main/java/org/apache/hadoop/hbase/master/ServerManager.java