Only produce when a consumer is ready

main.go

package main

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

func Produce(values chan<- int, ready <-chan bool) {
	for {
		<-ready
		fmt.Println("Produced a value!")
		values <- 42
	}
}

func Consume(values <-chan int, ready chan<- bool) {
	ready <- true

	for v := range values {
		fmt.Println(v)
		time.Sleep(5 * time.Second)
		ready <- true
	}
}

func main() {
	values := make(chan int)
	ready := make(chan bool)

	var wg sync.WaitGroup
	wg.Add(1)

	go Produce(values, ready)

	go Consume(values, ready)
	go Consume(values, ready)
	go Consume(values, ready)

	wg.Wait()
}