code: private static void sendResponse(PrintWriter out, SmtpResponse smtpResponse) {
  		if (smtpResponse.getCode() > 0) {
  			int code = smtpResponse.getCode();
  			String message = smtpResponse.getMessage();
  			out.print(code + " " + message + "\r\n");
  			out.flush();
  		}
  	}
docs: Send response to client.
  
  @param out socket output stream
  @param smtpResponse response object