code: @SuppressWarnings("unchecked")
    protected synchronized FileOutputFormat<K, V> getDelegate(Configuration conf) throws IOException {
      if (delegate == null) {
        delegate = BigQueryOutputConfiguration.getFileOutputFormat(conf);
        logger.atInfo().log("Delegating functionality to '%s'.", delegate.getClass().getSimpleName());
      }
      return delegate;
    }
docs: Gets a reference to the underlying delegate used by this OutputFormat.
  
  @param conf the configuration to derive the delegate from.
  @return the underlying wrapped delegate.
  @throws IOException if unable to get the delegate.