title: Is it possible to make such a proxy usage?
body: <p>I`m wondering if it is possible to implement following:</p>
  <p>I have some service in GO (used for Firebase Cloud Messaging) it uses go package from firebase (firebase.google.com/go/v4) to send messages. This packge sends https requests. And One of them is to <a href="https://oauth2.googleapis.com/token" rel="nofollow noreferrer">https://oauth2.googleapis.com/token</a> to get token.
  I can't change code in Firebase go-package, but I need to use proxy, that is why before sending message I need to set HTTPS_PROXY environment variable to my proxy address. It works fine.</p>
  <p>Now I need to do some automatic tests and I have an emulator that has /token endpoint and return a valid token as response. Is it possible to use some kind of proxy that can redirect https requests to my emulators endpoint so that all requests to <a href="https://oauth2.googleapis.com/token" rel="nofollow noreferrer">https://oauth2.googleapis.com/token</a> should be redirected to my emulators endpoint /token?
  And another question is there are any possible problems because of HTTPS ?
  Is it possible to get rid of https and use only http after the proxy?</p>