anchor.diff:                 [publickey_msg, password_msg, keyboard_interactive_msg])
       ];
   
  -dbg_ssh(hostkey) ->
  +dbg_ssh0(hostkey) ->
       [dbg:tpl(ssh_transport, verify_host_key, 4, x),
        dbg:tp(ssh_transport, verify, 4, x),
        dbg:tpl(ssh_transport, known_host_key, 3, x),
  
positive.code:      dbg:tpl(ssh_transport, is_host_key, 5, x)
      ];
  
  dbg_ssh(msg) ->
      [dbg_ssh(hostkey),
       dbg_ssh(auth),
       dbg:tp(ssh_message,encode,1, x),
       dbg:tp(ssh_message,decode,1, x),
       dbg:tpl(ssh_transport,select_algorithm,4, x),
  
negative.code: 
  %%%----------------------------------------------------------------
  -record(data, {writer,
                 initialized,
                 acc}).
  
  fmt(Fmt, Args,  D=#data{initialized=false}) ->
      fmt(Fmt, Args,
          D#data{acc = (D#data.writer)("~s~n", [initial_info()], D#data.acc),
                 initialized = true}
         );
  fmt(Fmt, Args,  D=#data{writer=Write, acc=Acc}) ->
      D#data{acc = Write(Fmt,Args,Acc)}.
  
  