Why running Golang's time.Now() at OpenWRT always get UTC time?

I wrote a Golang program that runs on OpenWRT.

package main

import (
    "fmt"
    "time"
)

func main(){
    fmt.Println(time.Now())
}

When I run this program on my Macbook, I always get the correct local time.

However, when running this program on OpenWRT, I always get UTC time.

I have set the time zone and time of OpenWRT. When I execute uci show system, I can see the right time zone. When I execute date the right local time can be display correctly.

So my question is, how do I get the correct local time using Golang's time.Now() on OpenWRT?

The root of my problem is that my OpenWRT lacks the zoneinfo package. So I run opkg update && opkg install zoneinfo-xxx first.

This is part of go/src/time/zoneinfo_unix.go:

func initLocal() {
    // consult $TZ to find the time zone to use.
    // no $TZ means use the system default /etc/localtime.
    // $TZ="" means use UTC.
    // $TZ="foo" means use /usr/share/zoneinfo/foo.

    ...

}

According to this file, if there is no "TZ" variable, Golang will use the time zone pointed to by /etc/localtime when calling time.Now().

Then I set time zone at /etc/config/system (option zonename 'xxxxxx') and run /etc/init.d/system restart. Finally, I can get the correct time.Now().