Httpx 0.28.1 Configuration Proxy Header

[Kiupii]

Hello,

I'm working on a project and we use Httpx to make call to an API threw a proxy and we would like to up our version to 0.28.1.

Until version 0.27.2, in Client object, parameter proxies was deprecated but still available. So we use it to make our configuration as it :

class ApiService:
  
    def __int__(*args):
        self._proxy_token = [token]
        headers = httpx.Headers({"X-Goog-Iap-Jwt-Assertion": self._proxy_token})
        proxy = httpx.Proxy(url=f"http://{proxy_url}:80", headers=headers)
        self._proxy = {"http://": proxy, "https://": proxy}
        .......


    def call_api(*args):
       cert = (
            ....
        )
        with httpx.Client(proxies=self._proxy, cert=cert, verify=self._cert) as client:
           # our call

I seen in this post #2879 that, in the new version, the way to make this was to use parameter mount with HTTPTransport object.

import httpx

# instead of
# client = httpx.Client(
#    proxies={"http://": "http://127.0.0.1:80", "https://": "https://127.0.0.1:443"}
# )
# do ...
client = httpx.Client(
   mounts={
       "http://": httpx.HTTPTransport(proxy="http://127.0.0.1:80"),
       "https://": httpx.HTTPTransport(proxy="https://127.0.0.1:443"),
   }
)

But when i am looking into Httpx documentations (for Client or HTTPTransport) or anywhere else, i don't find how to pass my proxy headers with HTTPTransport.

Can anyone enlighten me ?
Thanks in advance.