[优化] nettop 可以输出csv格式,更好解析

环境：

```sh
% sw_vers
ProductName:    macOS
ProductVersion: 12.0.1
BuildVersion:   21A559
```


示例：
```sh
% nettop -L 1 -P -J bytes_in,bytes_out
,bytes_in,bytes_out,
systemstats.503,0,0,
configd.504,0,0,
apsd.533,11417,23504,
locationd.541,0,0,
bluetoothd.555,0,0,
```