pkg/types/set.go
func (us *unsafeSet) Copy() Set {
	cp := NewUnsafeSet()
	for val := range us.d {
		cp.Add(val)
	}

	return cp
}
func (us *unsafeSet) Copy() Set {
	cp := NewUnsafeSet()
	for val := range us.d {
		cp.Add(val)
	}

	return cp
}
// Copy creates a new Set containing the values of the first