public TransitRegionStateProcedure createOneAssignProcedure(RegionInfo ri, boolean override,
    boolean force) {
    TransitRegionStateProcedure trsp = null;
    try {
      trsp = createAssignProcedure(ri, null, override, force);
    } catch (IOException ioe) {
      LOG.info(
        "Failed {} assign, override={}"
          + (override ? "" : "; set override to by-pass state checks."),
        ri.getEncodedName(), override, ioe);
    }
    return trsp;
  }
Create one TransitRegionStateProcedure to assign a region w/o specifying a target server. This
method is called from HBCK2.
@return an assign or null
hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/AssignmentManager.java