code: public static SafeCloseSmtpServer start(int port) {
  		SafeCloseSmtpServer server = new SafeCloseSmtpServer(port);
  		Thread t = new Thread(server, "Mock SMTP Server Thread");
  		t.start();
  
  		// Block until the server socket is created
  		try {
  			server.startupBarrier.await();
  		} catch (InterruptedException e) {
  			log.log(Level.WARNING, "Interrupted", e);
  		}
  
  		return server;
  	}
docs: Creates an instance of SimpleSmtpServer and starts it.
  
  @param port port number the server should listen to
  @return a reference to the SMTP server