@Override
  public void setPriority(TableName tn) {
    delegate.setPriority(tn);
  }
Simple delegating controller for use with the {@link RpcControllerFactory} to help override
standard behavior of a {@link HBaseRpcController}. Used testing.
hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/DelegatingHBaseRpcController.java