code: public void setProxy(String host, int port, String user, String pwd) {
  		this.proxy = new Proxy(host, port, user, pwd);
  	}
docs: sets proxy, optionally using basic authentication
  
  @param host	proxy host
  @param port	proxy port
  @param user	proxy user or null when no authentication is needed
  @param pwd	proxy password or null when no authentication is needed