Provide a user API for retrieving additional parameters from request cookies

[jackm]

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Is your feature related to a problem? Please describe.

Provide a user API for retrieving httpx.Cookie object parameters from request cookies such as cookie expiry date, cookie path, secure flag, etc.
Right now it is only possible to get a cookie's value via httpx.Cookies.get(). No other cookie parameters are exposed via a user accessible API.

Describe alternatives you considered

The only way to get these parameters is to manually pull them out of the cookie jar by accessing the internal variables. This should be discouraged as internal implementation details are not guaranteed to be stable after each new version. Also due to the way objects in the cookie jar are structured you need to know the cookie path ahead of time to use as a dict key in order to access the httpx.Cookie object within.

e.g.

>>> r = httpx.get('http://httpbin.org/cookies/set?chocolate=chip', allow_redirects=False)
>>> r.cookies.jar._cookies[r.request.url.host]['/']['chocolate']
Cookie(version=0, name='chocolate', value='chip', port=None, port_specified=False, domain='httpbin.org', domain_specified=False, domain_initial_dot=False, path='/', path_specified=True, secure=False, expires=None, discard=True, comment=None, comment_url=None, rest={}, rfc2109=False)

Additional context

See discussions/1497