Hi there! Thanks for all you do with Sentry -- it adds incredible value to our team.

I have a question about support for HTTP proxy authentication in sentry_sdk.

TL;DR: Is proxy authentication supported? If not, can it be? Without support for proxy auth, we can't use Sentry from a significant portion of our services.

More details:

I see that we can pass a https_proxy kwarg to sentry_sdk.init(), such as:

sentry_sdk.init("https://...@foo.ingest.sentry.io/...", https_proxy="http://user:pass@proxy")

However, it looks like that proxy string eventually gets passed to urllib3.ProxyManager() here:

Unfortunately, urllib3.ProxyManager does not appear to respect credentials passed in this string. The documentation isn't super clear on this, but it does allude to it in the description of the proxy_headers kwarg: "Could be used for proxy authentication." We verified with packet captures that urllib3.ProxyManager is not adding a Proxy-Authorization HTTP header to requests when the proxy string includes credentials.

Thanks so much for your consideration and help with this!