From Errors are Values (https://blog.golang.org/errors-are-values) – a pretty fantastic use of closures. Each of those writes passes along the result of the write to the next command and exits *before* trying the next step. This may solve an issue I've been having in several languages.

wow_closures_in.go

var err error
write := func(buf []byte) {
    if err != nil {
        return
    }
    _, err = w.Write(buf)
}
write(p0[a:b])
write(p1[c:d])
write(p2[e:f])
// and so on
if err != nil {
    return err
}