func getRandomRange(minN, maxN int, seed int64) int {
	// special value -1 means no explicit seeding.
	if seed == -1 {
		return rand.New(rand.NewSource(time.Now().UnixNano())).Intn(maxN-minN) + minN
	}
	return rand.New(rand.NewSource(seed)).Intn(maxN-minN) + minN
}

// Randomizes the order of bytes in the byte array
// using Knuth Fisher-Yates shuffle algorithm.
func randomizeBytes(s []byte, seed int64) []byte {

		}

		// While not recommended, it is valid to append to a shifted buffer.
		// This forces Write to copy the input.
		if rn.Intn(8) == 0 && cap(b) > 0 {
			b = b[1:1:cap(b)]
		}

		// Append a random integer of varying width.
		n := int64(rn.Intn(1 << rn.Intn(30)))
		want = append(strconv.AppendInt(want, n, 10), ' ')
		b = append(strconv.AppendInt(b, n, 10), ' ')
		w.Write(b)
	}
	w.Flush()

}

var makeFieldsInput = func() []byte {
	x := make([]byte, 1<<20)
	// Input is ~10% space, ~10% 2-byte UTF-8, rest ASCII non-space.
	r := rand.New(rand.NewSource(99))
	for i := range x {
		switch r.Intn(10) {
		case 0:
			x[i] = ' '
		case 1:
			if i > 0 && x[i-1] == 'x' {
				copy(x[i-1:], "χ")
				break
			}
			fallthrough
		default:
			x[i] = 'x'
		}
	}
	return x

		t.Fatalf("%s : %s", instanceType, err.Error())
	}

	z := obj.(*erasureServerPools)
	er := z.serverPools[0].sets[0]

	erasureDisks := er.getDisks()
	ridx := rand.Intn(len(erasureDisks))

	z.serverPools[0].erasureDisksMu.Lock()
	er.getDisks = func() []StorageAPI {
		erasureDisks[ridx] = newNaughtyDisk(erasureDisks[ridx], nil, errFaultyDisk)
		return erasureDisks
	}