package main

import (
    "fmt"
    "time"
    )

func thisTakesForever(id int, ch chan<- string) {
    time.Sleep(time.Second * 2)
    ch <- "done"
}

func main() {
    start := time.Now()

    buffer := 3
    ch := make(chan string, buffer)
    
    go thisTakesForever(111, ch)
    go thisTakesForever(222, ch)
    go thisTakesForever(333, ch)
    
    for len(ch) < buffer {        
    }

    close(ch)
    
    fmt.Println("Done in", time.Since(start))
}