anchor.diff:  %% @private
   -spec upgrade_reply(cowboy_http:status(), cowboy_http:headers(), #http_req{})
   	-> {ok, #http_req{}}.
  -upgrade_reply(Status, Headers, Req=#http_req{socket=Socket, transport=Transport,
  +upgrade_reply(Status, Headers, Req=#http_req{
   		pid=ReqPid, resp_state=waiting, resp_headers=RespHeaders}) ->
  -	Head = response_head(Status, Headers, RespHeaders, [
  +	response(Status, Headers, RespHeaders, [
   		{<<"Connection">>, <<"Upgrade">>}
  -	]),
  -	Transport:send(Socket, Head),
  +	], Req),
   	ReqPid ! {?MODULE, resp_sent},
   	{ok, Req#http_req{resp_state=done, resp_headers=[], resp_body= <<>>}}.
   
  
positive.code: 	{ok, Transport, Socket}.
  
  %% Internal.
  
  -spec response_connection(cowboy_http:headers(), keepalive | close)
  	-> keepalive | close.
  
negative.code: 	Tokens = cowboy_http:nonempty_list(ReplyConn, fun cowboy_http:token/2),
  	cowboy_http:connection_to_atom(Tokens).
  
  -spec response_merge_headers(cowboy_http:headers(), cowboy_http:headers(),
  	cowboy_http:headers()) -> cowboy_http:headers().
  response_merge_headers(Headers, RespHeaders, DefaultHeaders) ->
  	Headers2 = [{header_to_binary(Key), Value} || {Key, Value} <- Headers],
  	merge_headers(
  		merge_headers(Headers2, RespHeaders),
  		DefaultHeaders).
  
  -spec merge_headers(cowboy_http:headers(), cowboy_http:headers())
  	-> cowboy_http:headers().
  