anchor.diff:  -export([
      new/0,
      new/1,
  -   state/1, 
  +   state/1,
  +   header/2,
  +   header/3,   
      decode/1, 
      decode/2, 
      encode/1, 
  
positive.code: state(#http{is=chunk_tail}) -> payload;
  state(#http{is=eoh})     -> eoh;
  state(#http{is=eof})     -> eof.
  
  %%
  %% decodes http stream 
  
negative.code: %% public types 
  -type(method()  :: atom()).                        % request method
  -type(url()     :: binary()).                      % request url 
  -type(header()  :: {atom() | binary(), binary() | integer}).  % http header
  -type(request() :: {method(), url(), [header()]}). % http request
  -type(response():: {integer(), binary(), [header()]}). 
  -type(payload() :: binary()).                      % http payload
  