private List<RegionInfo> getRegionInfoList(final MasterProcedureEnv env) throws IOException {
    return env.getAssignmentManager().getRegionStates().getRegionsOfTable(getTableName());
  }
Fetches all Regions for a table. Cache the result of this method if you need to use it multiple
times. Be aware that it may change over in between calls to this procedure.
hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/ModifyTableProcedure.java