reader := bytes.NewReader(data)
	for {
		// Using io.Copy instead of this loop will not work for us as io.Copy
		// will use bytes.Reader.WriteTo() which will not do shardSize'ed writes
		// causing error.
		n, err := reader.Read(shard)
		w.Write(shard[:n])
		if err == nil {
			continue
		}
		if err == io.EOF {
			break
		}
		t.Fatal(err)
	}
	w.(io.Closer).Close()