anchor.diff:  			%% @todo We need to kill the stream if it tries to send data before headers.
   			%% @todo Same as above.
   			case lists:keyfind(StreamID, #stream.id, Streams) of
  +				#stream{method= <<"HEAD">>} ->
  +					ok;
   				#stream{version='HTTP/1.1'} ->
   					Transport:send(Socket, [
   						integer_to_binary(Size, 16), <<"\r\n">>, Data,
  
positive.code: 	id = undefined :: cowboy_stream:streamid(),
  	%% Stream handlers and their state.
  	state = undefined :: {module(), any()},
  	%% Client HTTP version for this stream.
  	version = undefined :: cowboy:http_version(),
  	%% Unparsed te header. Used to know if we can send trailers.
  
negative.code: 		0 ->
  			%% We send the last chunk only if version is HTTP/1.1 and IsFin=fin.
  			case lists:keyfind(StreamID, #stream.id, Streams) of
  				#stream{method= <<"HEAD">>} ->
  					ok;
  				#stream{version='HTTP/1.1'} when IsFin =:= fin ->
  					Transport:send(Socket, <<"0\r\n\r\n">>);
  				_ ->
  