38.18. 使用带有额外 Java 邮件发送器属性的标头

    .setHeader("from", constant("reply2me@foo.com"));
    .setHeader("java.smtp.from", method(UUID.class, "randomUUID"));
    .to("smtp://mymailserver:1234");

    .setHeader("from", constant("reply2me@foo.com"));
    .setHeader("java.smtp.from", method(UUID.class, "randomUUID"));
    .to("smtp://mymailserver:1234");