package main

import (
    "fmt"
    "log"
    "time"
)

func main() {
    bobCh := generate("bob", time.Second)
    sueCh := generate("sue", time.Second*4)

    output := fanIn(bobCh, sueCh)

    for val := range output {
        log.Println(val)
    }

    /*
        Output:
        2017/06/07 13:02:33 bob 0
        2017/06/07 13:02:33 sue 0
        2017/06/07 13:02:34 bob 1
        2017/06/07 13:02:35 bob 2
        2017/06/07 13:02:36 bob 3
        2017/06/07 13:02:37 sue 1
        2017/06/07 13:02:37 bob 4
        2017/06/07 13:02:38 bob 5
        2017/06/07 13:02:39 bob 6

    */
}

func fanIn(inputs ...<-chan string) <-chan string {
    output := make(chan string)

    for _, ch := range inputs {
        go func(output chan string, input <-chan string) {
            for s := range input {
                output <- s
            }
        }(output, ch)
    }

    return output
}

func generate(val string, delay time.Duration) <-chan string {
    output := make(chan string)

    go func() {
        for i := 0; ; i++ {
            output <- fmt.Sprintf("%s %d", val, i)
            time.Sleep(delay)
        }
    }()

    return output
}