default void preGetConfiguredNamespacesAndTablesInRSGroup(
    final ObserverContext<MasterCoprocessorEnvironment> ctx, final String groupName)
    throws IOException {
  }
Called before getting the configured namespaces and tables in the region server group.
@param ctx       the environment to interact with the framework and master
@param groupName name of the region server group
hbase-server/src/main/java/org/apache/hadoop/hbase/coprocessor/MasterObserver.java