# File lib/cool.io/dns_resolver.rb, line 131
    def request_question(hostname)
      raise ArgumentError, "hostname cannot be nil" if hostname.nil?

      # Query name
      message = hostname.split('.').map { |s| [s.size].pack('C') << s }.join + "\0"

      # Host address query
      qtype = 1

      # Internet query
      qclass = 1

      message << [qtype, qclass].pack('nn')
    end