// sync.Once is concurrent, not needed here
sync.Once is concurrent, not needed here
// sync . Once is concurrent not needed here
func (rs *doOnce) Do(f func()) {
	if *rs {
		*rs = false
		if f != nil {
			f()
		}
	}
}
func ( rs * doOnce ) Do ( f func ( ) ) { if * rs { * rs = false if f != nil { f ( ) } } }
sync.Once is concurrent, not needed here
sync . Once is concurrent not needed here