// writeParallel handles scheduling parallel execution of data write functions.
func writeParallel(wg *sync.WaitGroup, fn writeFn, ctxt *Link, seek, vaddr, length uint64) {
	if out, err := ctxt.Out.View(seek); err != nil {
		ctxt.Out.SeekSet(int64(seek))
		fn(ctxt, ctxt.Out, int64(vaddr), int64(length))
	} else {
		wg.Add(1)
		go func() {
			defer wg.Done()
			fn(ctxt, out, int64(vaddr), int64(length))

		if _, err := io.CopyN(f, rand.Reader, nBytes); err != nil {
			return nil, nil, fmt.Errorf("failed to write data to file: %v", err)
		}
		if _, err := f.Seek(0, 0); err != nil {
			return nil, nil, fmt.Errorf("failed to seek to front: %v", err)
		}

		done = func() {
			f.Close()
			os.Remove(f.Name())
		}

		return f, done, nil
	}