anchor.diff:        S
      }.   
   
  +%%
  +%%
   maybe_sent(ok, S) ->
      {next_state, 
         'ESTABLISHED', 
  
positive.code:    ?DEBUG(tcp, Addr, Peer, Pckt),
     % TODO: flexible flow control
     ok = inet:setopts(Sock, [{active, once}]),
     {emit, 
        {tcp, Peer, Pckt},
        'ESTABLISHED',
        S
     };
     
  'ESTABLISHED'({send, _Peer, Pckt}, #fsm{}=S) ->
     maybe_sent(send(Pckt, S), S);
  
negative.code:    peer,   % peer address  
     addr,   % local address
  
     packet, % frame i/o streams into packet(s)
     chunk,  % partially received frame   
  
     opts      % connection option
  }). 
  
  