code: public void
  run(ZoneTransferHandler handler) throws IOException, ZoneTransferException {
  	this.handler = handler;
  	try {
  		openConnection();
  		doxfr();
  	}
  	finally {
  		closeConnection();
  	}
  }
docs: Does the zone transfer.
  @param handler The callback object that handles the zone transfer data.
  @throws IOException The zone transfer failed to due an IO problem.
  @throws ZoneTransferException The zone transfer failed to due a problem
  with the zone transfer itself.