def size
      return 1 if @to.nil?
      from = IPAddr.new(@from)
      to   = IPAddr.new(@to)
      (from..to).to_a.size
    end
def size
      return 1 if @to.nil?
      from = IPAddr.new(@from)
      to   = IPAddr.new(@to)
      (from..to).to_a.size
    end
@overload initialize(ip)
   @param [#to_s] from the IP single IP address.
   @example
     Nexpose::IPRange.new('192.168.1.0')

 @overload initialize(start_ip, end_ip)
   @param [#to_s] from the IP to start the range with.
   @param [#to_s] to the IP to end the range with.
   @example
     Nexpose::IPRange.new('192.168.1.0', '192.168.1.255')

 @overload initialize(cidr_range)
   @param [#to_s] from the CIDR notation IP address range.
   @example
     Nexpose::IPRange.new('192.168.1.0/24')
   @note The range will not be stripped of reserved IP addresses (such as
     x.x.x.0 and x.x.x.255).

 @return [IPRange] an IP address range of one or more addresses.
 Size of the IP range. The total number of IP addresses represented
 by this range.

 @return [Fixnum] size of the range.