Trying to get a unique ID per instance by using UnixNano + a mutex lock: https://play.golang.org/p/q8OzAXzha3B

unique_sequence_id.go

package main

import (
	"fmt"
	"sync"
	"time"
)

type Sequence struct {
	m sync.Mutex
}

func (s *Sequence) Next() int64 {
	s.m.Lock()
	defer s.m.Unlock()
	return time.Now().UnixNano()
}

func main() {
	s := Sequence{}
	
	for i := 0; i < 10; i++ {
		go func() { 
			fmt.Println(s.Next()) 
		}()
	}
	
	time.Sleep(time.Millisecond)
}

• https://github.com/lpar/serial/blob/master/serial.go (with checks to ensure each number is larger than the last)
• https://gist.github.com/rbastic/304e2a0e50db8d315ff7c85d817f4872
• https://github.com/golang/proposal/blob/master/design/12914-monotonic.md