[2h]

here is some Go code that does the same thing:

    package unix
    
    import "time"
    
    // 2023-03-04 11:35:43.4859519 -0600 CST
    func unix_nano(nsec int64) string {
       return time.Unix(0, nsec).String()
    }

https://godocs.io/time#Unix