# File lib/net/ssh/known_hosts.rb, line 121
    def add(host, key)
      File.open(source, "a") do |file|
        blob = [Net::SSH::Buffer.from(:key, key).to_s].pack("m*").gsub(/\s/, "")
        file.puts "#{host} #{key.ssh_type} #{blob}"
      end
    end