type lockedRandSource struct {
	lk  sync.Mutex
	src rand.Source
}

// Int63 returns a non-negative pseudo-random 63-bit integer as an int64.
func (r *lockedRandSource) Int63() (n int64) {
	r.lk.Lock()
	n = r.src.Int63()
	r.lk.Unlock()
	return
}

// Seed uses the provided seed value to initialize the generator to a
// deterministic state.

pkg math/big, method (*Int) Sqrt(*Int) *Int
pkg math/rand, func Uint64() uint64
pkg math/rand, method (*Rand) Uint64() uint64
pkg math/rand, type Source64 interface, Int63() int64
pkg math/rand, type Source64 interface { Int63, Seed, Uint64 }
pkg math/rand, type Source64 interface, Seed(int64)
pkg math/rand, type Source64 interface, Uint64() uint64
pkg net/http, const TrailerPrefix ideal-string

var src = rand.NewSource(time.Now().UnixNano())

func randString(n int) string {
	b := make([]byte, n)
	// A src.Int63() generates 63 random bits, enough for letterIdxMax characters!
	for i, cache, remain := n-1, src.Int63(), letterIdxMax; i >= 0; {
		if remain == 0 {
			cache, remain = src.Int63(), letterIdxMax
		}
		if idx := int(cache & letterIdxMask); idx < len(letterBytes) {
			b[i] = letterBytes[idx]
			i--

	// 4 MB block.
	// Approx runtime ~30ms
	data := make([]byte, 4<<20)
	rng := rand.New(rand.NewSource(0))
	for i := range data {
		// Generate compressible stream...
		data[i] = byte(rng.Int63() & 3)
	}
	failOnErr := func(err error) {
		if err != nil {
			logger.Fatal(errSelfTestFailure, "compress: error on self-test: %v", err)
		}
	}
	const skip = 2<<20 + 511

<li>Many methods now use faster algorithms that were not possible to adopt in <code>math/rand</code>
because they changed the output streams.

<li>The
<code>Intn</code>,
<code>Int31</code>,
<code>Int31n</code>,
<code>Int63</code>,
and
<code>Int64n</code>
top-level functions and methods from <code>math/rand</code>
are spelled more idiomatically in <code>math/rand/v2</code>:
<code>IntN</code>,
<code>Int32</code>,

pkg math/rand, method (*Rand) Uint32() uint32
pkg math/rand, method (*Zipf) Uint64() uint64
pkg math/rand, type Rand struct
pkg math/rand, type Source interface { Int63, Seed }
pkg math/rand, type Source interface, Int63() int64
pkg math/rand, type Source interface, Seed(int64)
pkg math/rand, type Zipf struct
pkg mime, func AddExtensionType(string, string) error