anchor.diff:           <<Chunk:Len/binary, Rest/binary>> = Buffer,
            {emit,
               [{http, Uri, Chunk}, {http, Uri, eof}],
  -            'IO',
  +            'ACTIVE',
               S#fsm{
                  buffer = Rest
               }
  
positive.code:          if 
              % this is last chunk
              Len =:= 0 -> 
                 {emit, {http, Uri, eof}, 'IO', S};
              % this is interim chunk   
              true      ->
                 parse_chunk(S#fsm{iolen=Len, buffer=Data})
  
negative.code: %%% ACTIVE
  %%%
  %%%------------------------------------------------------------------   
  'ACTIVE'(timeout, S) ->
     % temporary hack here to control message timeout
     {next_state, 'ACTIVE', S};
  
  'ACTIVE'({Prot, _Peer, terminated}, #fsm{prot=P}=S)
   when Prot =:= P ->
     {stop, normal, S};
  