default TableDescriptor preCreateTableRegionsInfos(
    final ObserverContext<MasterCoprocessorEnvironment> ctx, TableDescriptor desc)
    throws IOException {
    return desc;
  }
Called before we create the region infos for this table. Called as part of create table RPC
call.
@param ctx  the environment to interact with the framework and master
@param desc the TableDescriptor for the table
@return the TableDescriptor used to create the table. Default is the one passed in. Return
        {@code null} means cancel the creation.
hbase-server/src/main/java/org/apache/hadoop/hbase/coprocessor/MasterObserver.java