HTTPX Transport

[nihaals]

HTTPX is a HTTP library for Python which supports both sync and async requests. A big advantage of HTTPX is that it supports Trio (as well as asyncio), something not available with the current AIOHTTP Transport

[KingDarBoja]

The important part is documented at https://www.python-httpx.org/async/#supported-async-environments

Would be great to include another transport that make use of Trio, however I am a bit worried by the amount of packages being installed to use this library as stated at #147.

[nihaals]

Should this be marked as blocked by #147? I do agree that this issue should be solved first but it shouldn't be too hard to find a solution

[KingDarBoja]

No need to be blocked, this can be added into the library and later see if we can solve the optional dependencies.