func math/rand.NewSource

3 uses

	math/rand (current package)
		rand.go#L44: func NewSource(seed int64) Source {
		rand.go#L293: var globalRand = New(&lockedSource{src: NewSource(1).(*rngSource)})

	math/big
		prime.go#L93: 	rand := rand.New(rand.NewSource(int64(n[0])))