read_entity_body() should warn() if Content-Length is less than the size of the payload.

https://tools.ietf.org/html/rfc2616#page-34

The last paragraph of RFC 2616/4.4 stipulates that a notification (warn() in Perl, ISTM) should be given when the payload length doesn’t match the Content-Length header.

Right now there’s no such warn() happening … maybe do a recv()/MSG_PEEK to see if there is more to read on the socket, then warn() if so?