Write bytes forever

main.go

package main

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

func main() {
        var mu sync.Mutex
        var wrote int
        var lastWrite time.Time
        go func() {
                for range time.Tick(time.Second) {
                        mu.Lock()
                        fmt.Fprintf(os.Stderr, "wrote %d bytes %v ago\n", wrote, time.Since(lastWrite))
                        mu.Unlock()
                }
        }()
        for {
                n, err := os.Stdout.Write([]byte("A"))
                if err != nil {
                        break
                }
                mu.Lock()
                wrote += n
                lastWrite = time.Now()
                mu.Unlock()
        }
}