Set proxy for a single request

[AneryCoft]

We can only create a global proxy when the client is instantiated.
Whether to add proxy parameters in every client requests？

[tomchristie]

So, httpx does not currently allow setting proxies per-request. You need to configure a client specifically for the request.

If anyone is interested in understanding why this is the case I'd suggest taking a look at the Transport API, and implementation of the default HTTP transport.

Proxy configuration is dealt with on instantiating the transport, since the handle_request(Request) -> Response API is kept deliberately simple.

I'm happy to discuss more with anyone who's interested how we might go about resolving this, if anyone is keen on an in-depth design discussion. (fun) 🥳