Go에서 장기 실행 프로세스에 대해 시각적으로 매력적인 대기/바쁨 표시기를 어떻게 만들 수 있나요?

<code class="go">package main

import (
    "fmt"
    "log"
    "os/exec"
    "time"
)

func indicator(shutdownCh <-chan struct{}) {
    ticker := time.NewTicker(time.Second)
    defer ticker.Stop()
    for {
        select {
        case <-ticker.C:
            fmt.Print(".")
        case <-shutdownCh:
            return
        }
    }
}

func main() {
    cmd := exec.Command("npm", "install")
    log.Printf("Running command and waiting for it to finish...")

    // Start indicator:
    shutdownCh := make(chan struct{})
    go indicator(shutdownCh)

    err := cmd.Run()

    close(shutdownCh) // Signal indicator() to terminate

    fmt.Println()
    log.Printf("Command finished with error: %v", err)
}</code>

<code class="go">func indicator(shutdownCh <-chan struct{}) {
    ticker := time.NewTicker(time.Second)
    defer ticker.Stop()
    for i := 0; ; {
        select {
        case <-ticker.C:
            fmt.Print(".")
            if i++; i%5 == 0 {
                fmt.Println()
            }
        case <-shutdownCh:
            return
        }
    }
}</code>