We definitely need a way to bypass the encoding. One of my problems with jQuery ajax is how hard it is to send JSON data to the server. IMO it would be best to not do any encoding in `net/request`. It would always send the data (when provided) verbatim as the request body. Then helper functions could be made that would encode it in form encoding, query parameters, etc.

Currently this is totally broken for `POST` requests, since `encode` prepends the `?` query string character, which it should not for a `POST` request.