get real-world time in Go playground

playground_realtime.go

package main

import (
	"fmt"
	"time"
	_ "unsafe"
)

//go:linkname faketime runtime.faketime
var faketime int64

func main() {
	fmt.Println(faketime)
	fmt.Println(time.Now())
	faketime = 0
	fmt.Println(faketime)
	fmt.Println(time.Now())
}