code: func NewCIDRRange(cidr *net.IPNet) *Range {
  	return NewAllocatorCIDRRange(cidr, func(max int, rangeSpec string) allocator.Interface {
  		return allocator.NewAllocationMap(max, rangeSpec)
  	})
  }
docs: // Helper that wraps NewAllocatorCIDRRange, for creating a range backed by an in-memory store.