main.go

package main

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

func WellCome1(s string, in chan int) {
	for i := 0; i < 5; i++ {
		in <- i + 2
		fmt.Println(s, ":", i)
	}
}

func WellCome2(s string, out chan int) {
	for i := 0; i < 5; i++ {
		time.Sleep(50 * time.Millisecond)
		result := <-out
		fmt.Println(s, ":", result)
	}
}

var wg sync.WaitGroup

func main() {
	ch := make(chan int)
	go WellCome1("wellcome1", ch)
	go WellCome2("wellcome2", ch)
	time.Sleep(300 * time.Millisecond)
	fmt.Println("hello main ")
}

result

wellcome2 : 2
wellcome2 : 3
wellcome2 : 4
wellcome2 : 5
wellcome2 : 6
hello main