class Gem::Resolv::DNS::Requester::ConnectedUDP

def close
  @mutex.synchronize do
    if @initialized
      super
      @senders.each_key {|from, id|
        DNS.free_request_id(@host, @port, id)
      }
      @initialized = false
    end
  end
end

def initialize(host, port=Port)
  super()
  @host = host
  @port = port
  @mutex = Thread::Mutex.new
  @initialized = false
end

def lazy_initialize
  @mutex.synchronize {
    next if @initialized
    @initialized = true
    is_ipv6 = @host.index(':')
    sock = UDPSocket.new(is_ipv6 ? Socket::AF_INET6 : Socket::AF_INET)
    @socks = [sock]
    sock.do_not_reverse_lookup = true
    DNS.bind_random_port(sock, is_ipv6 ? "::" : "0.0.0.0")
    sock.connect(@host, @port)
  }
  self
end

def recv_reply(readable_socks)
  lazy_initialize
  reply = readable_socks[0].recv(UDPSize)
  return reply, nil
end

def sender(msg, data, host=@host, port=@port)
  lazy_initialize
  unless host == @host && port == @port
    raise RequestError.new("host/port don't match: #{host}:#{port}")
  end
  id = DNS.allocate_request_id(@host, @port)
  request = msg.encode
  request[0,2] = [id].pack('n')
  return @senders[[nil,id]] = Sender.new(request, data, @socks[0])
end