为什么在使用`log.Println`和`fmt.Println`时改变输出顺序？

Here is my code: package main

import "log"
import "fmt"

func main() {
    var a string = "initail"
    log.Println(a)
    var b, c int = 1, 2
    fmt.Println(b, c)
}

The output is:

1 2
2016/12/30 14:22:58 initail

So i don't understand why the output's order? why log.Println is slower than fmt.Println?

Only difference between those in terms of its printing behaviour is

• log.Println writes to Stderr
• fmt.Println writes to Stdout

Both are not buffered. So the fact that StdOut came before StdError is specific to your terminal or environment.

Here is a play link https://play.golang.org/p/0cukg_a9GR