do_start

# File lib/net/pop.rb, line 543
    def do_start(account, password) # :nodoc:
      s = Timeout.timeout(@open_timeout, Net::OpenTimeout) do
        TCPSocket.open(@address, port)
      end
      if use_ssl?
        raise 'openssl library not installed' unless defined?(OpenSSL)
        context = OpenSSL::SSL::SSLContext.new
        context.set_params(@ssl_params)
        s = OpenSSL::SSL::SSLSocket.new(s, context)
        s.sync_close = true
        ssl_socket_connect(s, @open_timeout)
        if context.verify_mode != OpenSSL::SSL::VERIFY_NONE
          s.post_connection_check(@address)
        end
      end
      @socket = InternetMessageIO.new(s,
                                      read_timeout: @read_timeout,
                                      debug_output: @debug_output)
      logging "POP session started: #{@address}:#{@port} (#{@apop ? 'APOP' : 'POP'})"
      on_connect
      @command = POP3Command.new(@socket)
      if apop?
        @command.apop account, password
      else
        @command.auth account, password
      end
      @started = true
    ensure
      # Authentication failed, clean up connection.
      unless @started
        s.close if s
        @socket = nil
        @command = nil
      end
    end