Is there a way to specify a proxy for outgoing requests?
At work we have to pass requests that go to the internet trough a proxy. I have http_proxy and https_proxy environment variables set, and most command line utilities like curl, git and so on use those env vars, but when I do something like

--rewrite '/api/* -> https://external-service.example.com/api/$1'

the https://external-service.example.com/api/$1 requests do not use the proxy for the outgoing connection.
Am I doing something wrong, or is a proxy just not supported?