The returned data might be binary if it wasn't JSON.

The main goal is to check errors without sending the request.
Otherwise, the errors would be unpredictable due to race conditions.

For example, if there is a TLS error, and we try to send a request,
this would sometimes succeed, and sometimes fail.
Receiving the response could result in the 'closed' error or in a TLS error,
depending on the timing.

This is why neither of the clients (fusco, gun, httpc) can be used.
Instead, the 'ssl' module is used directly.

Otherwise, jiffy encodes them as lists of numbers,
which makes them unreadable.

The motivation is to eliminate flakiness caused by race conditions.

- Negative tests check TLS errors after connecting without sending
  any requests (which would cause the socket to return the 'closed'
  error if it was already closed)
- Positive tests use the same internal API to make them similar, and
  to check that the API can handle succeess and failure.
- Positive tests execute meaningful queries now.