bunyan创建的log文件里默认的一些字段可以删除吗？

Question

1

var logfile = bunyan.createLogger({
    name: 'log',
    time: new Date().getTime(),
    streams: [
      {
        level: 'debug',
        stream: accessLogStream2
      },
      {
        level: 'trace',
        stream: accessLogStream
      }
    ],
    serializers:{req: reqSerializer}
});

2

{"name":"log","time":1554173824734,"hostname":"B000000095297A","pid":36239,"level":10,"req":{"host":"localhost:3000","qs":{"debug":"false","type":"click"},"user_agent":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.121 Safari/537.36"},"msg":"","v":0}

第一段代码是配置log内容的部分，第二段是该配置打印出的日志。想问下我如果不想要hostname这个默认的字段该怎么操作。