# File lib/active_support/vendor/memcache-client-1.5.1/memcache.rb, line 787
    def socket
      @mutex.lock if @multithread
      return @sock if @sock and not @sock.closed?

      @sock = nil

      # If the host was dead, don't retry for a while.
      return if @retry and @retry > Time.now

      # Attempt to connect if not already connected.
      begin
        @sock = timeout CONNECT_TIMEOUT do
          TCPSocket.new @host, @port
        end
        if Socket.constants.include? 'TCP_NODELAY' then
          @sock.setsockopt Socket::IPPROTO_TCP, Socket::TCP_NODELAY, 1
        end
        @retry  = nil
        @status = 'CONNECTED'
      rescue SocketError, SystemCallError, IOError, Timeout::Error => err
        mark_dead err.message
      end

      return @sock
    ensure
      @mutex.unlock if @multithread
    end