better mem layout

peer/internal/uprng/uprng.go

@@ -33,11 +33,7 @@ const (
 // incrementing ChaCha20 nonce.
 type nonce struct {
 	limbs [3]uint32
-	bytes []byte
-}
-
-func newNonce() *nonce {
-	return &nonce{bytes: make([]byte, chacha20.NonceSize)}
+	bytes [chacha20.NonceSize]byte
 }
 
 func (n *nonce) inc() {
@@ -56,14 +52,13 @@ type prng struct {
 	read   int
 	t      time.Time
 	key    []byte
-	nonce  *nonce
+	nonce  nonce
 	mu     sync.Mutex
 }
 
 func newPRNG() *prng {
 	p := &prng{
-		nonce: newNonce(),
-		key:   make([]byte, chacha20.KeySize),
+		key: make([]byte, chacha20.KeySize),
 	}
 	p.seed()
 	return p
@@ -82,7 +77,7 @@ func (p *prng) seed() {
 	}
 
 	// never errors with correct key and nonce sizes
-	cipher, _ := chacha20.NewUnauthenticatedCipher(p.key, p.nonce.bytes)
+	cipher, _ := chacha20.NewUnauthenticatedCipher(p.key, p.nonce.bytes[:])
 	p.nonce.inc()
 
 	p.cipher = cipher