created a test server which removes the content-length. Taken extra
condition into account, that the close might manifest itself while
selecting on the socket; at that point we're out of the consumption
loop, so better not to deal with throwing :called
these will reapply options accordingly (i.e. HTTPX.with_headers(...)).
Because we now have these, HTTPX.headers and HTTPX.timeout have been
deprecated.
After looking at net-http code, decided to adopt the following
behaviour:
* do not send accept-encoding when sending Range header
* remove content-encoding from response headers as we decode them
in order for user code to track what was decoded, added
HTTPX::Response::Body#encodings, which returns the array of encodings
for which the body was successfully decoded
