func math/rand.NewSource

3 uses

	math/rand (current package)
		rand.go#L51: func NewSource(seed int64) Source {

	math/big
		prime.go#L95: 	rand := rand.New(rand.NewSource(int64(n[0])))

	testing
		testing.go#L2427: 		rng := rand.New(rand.NewSource(n))