# File lib/net/ssh/authentication/pageant.rb, line 168
      def read(n = nil)
        return nil unless @res
        if n.nil?
          start, @pos = @pos, @res.size
          return @res[start..-1]
        else
          start, @pos = @pos, @pos + n
          return @res[start, n]
        end
      end