When we write a file, how we make sure that file is written completely to disk. One of the way is write a temporary file first and then rename it, rename operation is atomic, so we get a complete file.

tempFile, err := ioutil.TempFile(path, name)
if err != nil {
    return err
}
defer tempFile.Close()

tempname := tempFile.Name()
defer os.Remove(tempname)

//Write to temp file

err = os.Rename(tempname, filename)
if err != nil {
    return err
}