@Override
  protected boolean startTransition(final MasterProcedureEnv env,
    final RegionStateNode regionNode) {
    // nothing to do here. we skip the step in the constructor
    // by jumping to REGION_TRANSITION_DISPATCH
    throw new UnsupportedOperationException();
  }
Leave here only for checking if we can successfully start the master.
@deprecated Do not use any more.
@see TransitRegionStateProcedure
hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/UnassignProcedure.java