event_emitter.go

package main

import (
	"log"
	"sync"
)

func main() {
	cond := sync.NewCond(&sync.Mutex{})
	var wg1 sync.WaitGroup
	var wg2 sync.WaitGroup
	wg1.Add(1)
	wg2.Add(1)
	go func() {
		defer wg2.Done()
		wg1.Done()
		cond.L.Lock()
		defer cond.L.Unlock()
		cond.Wait()
		log.Println("I received notification!")
	}()
	wg1.Wait()
	cond.Signal()
	wg2.Wait()
}