code: @Override
  	public void registerExtenderCallbacks(final IBurpExtenderCallbacks callbacks) {
  
  		// keep a reference to our callbacks object
  		this.callbacks = callbacks;
  
  		// obtain an extension helpers object
  		helpers = callbacks.getHelpers();
  
  		//get the output streams for info and error messages
  		stdout = callbacks.getStdout();
  		stderr = callbacks.getStderr();
  		
  		//put this into the local instance variable
  		instance = this;
  
  		//initialize the extension
  		initialize();
  
  		// set our extension name
  		callbacks.setExtensionName(extensionName);
  
  		callbacks.printOutput("Loaded " + extensionName);
  	}
docs: implement IBurpExtender