GetAuthHeader returns the Authorization header value to send to proxy u.

InvalidateCache invalidates the package-level cache for ProxyFromEnvironment.

ProxyFromEnvironment is like the standard library's http.ProxyFromEnvironment but additionally does OS-specific proxy lookups if the environment variables alone don't specify a proxy.

SetSelfProxy configures this package to avoid proxying through any of the provided addresses–e.g.

SetTransportGetProxyConnectHeader sets the provided Transport's GetProxyConnectHeader field, and adds logging of the received response.