joyent/http-parser — comment on commit b47c44d7a660d9ee6ab365864e345081f237b433
File: http_parser.c line 1739
By pgriess:

Yeah, if the client and server both agree on keep-alive (i.e. by both sending "Connection: keep-alive" headers), we're dealing with the same situation as HTTP/1.1: we have a bytestream that contains a response with no body followed by another response. The case we're dealing with here is not that we can't determine the response length -- it's that we know that the length is 0.