bug#23750: 25.0.95; bug in url-retrieve or json.el

[Stefan Monnier]

>> ¹  https://github.com/ternjs/tern/issues/719
> Investigation shows that the problem occurs when url-http-data is multibyte
> and (length url-http-data) differs from (length (string-as-unibyte
> url-http-data)), because we send a wrong value in Content-length.
> Changing url-http-create-request like this will make the problem more
> obvious for anyone else that hits it, patch attached.
> Stefan, did you have a particular situation in mind where this might be bad,
> when you wrote the FIXME?

No, nothing in particular.  Just that `string-as-unibyte` is generally
synonymous with "the author is confused about how coding systems work",
aka "trouble".


        Stefan