gistfile1.txt

package main

import (
    "bufio"
    "encoding/binary"
    "flag"
    "io"
    "os"
)

type SomeStruct struct {
    a, b, c int64
    d, e, f int
    g, h, i byte
}

func main() {
    buffer := flag.Bool("buffer", true, "buffer output stream")
    flag.Parse()

    v := SomeStruct{ 20, 40, 60, 10, 20, 30, 50, 30, 10 }

    f, err := os.Open("bin.dat", os.O_WRONLY | os.O_TRUNC | os.O_CREATE, 0666)
    if err != nil {
        panic(err)
    }
    defer f.Close()

    var w io.Writer
    if *buffer {
        w = bufio.NewWriter(f)
    } else {
        w = f
    }

    for i := 0; i < 1e6 ; i++ {
        binary.Write(w, binary.BigEndian, v)
    }

    if *buffer {
        w.(*bufio.Writer).Flush()   
    }
}