下面这个函数，放在click事件里面调用，任何callback都没有被调用，在vue的created里面调用就是正常的：

    detectNetwork(host, port, timeout=1000) {
        var net = require('net');
        console.log('detectHostPort, host:', host)
        console.log('detectHostPort, port:', port)
        console.log('detectHostPort, timeout:', timeout)
        var client = new net.Socket();
        client.setTimeout(500);
        
        console.log('detectNetwork detecting ...')
        client.connect(parseInt('8000'), '127.0.0.1', function(){
          console.log('connect, ok!!!!')
        })

        client.on('error', function(e) {
            console.log(e);
        });

        client.on('close', function() {
            console.log('Connection closed');
        });
    },