We need to favor "Transfer-Encoding: chunked" over the value of
the Content-Length header. We should also reject bogus,
duplicate and/or unreasonable values for both these, since they
can trigger unexpected behavior when combined with other HTTP
parsers in proxies such as varnish, nginx, haproxy, etc...
See RFC 7230 (and RFC 2616) for more details:
https://tools.ietf.org/html/rfc7230
https://www.rfc-editor.org/errata_search.php?rfc=7230