golang rand binary

rand.go

package main

import (
	"crypto/rand"
	"io"
	"bytes"
	"bufio"
	"fmt"
)

func main() {
	var b bytes.Buffer
	size := 5
	
	out := bufio.NewWriterSize(&b, size)
	
	in := rand.Reader

	_, _ = io.CopyN(out, in, int64(size))
	
	fmt.Printf("%v", b.Bytes()[:size])
	
}