How to format a request with client side certificates in HTTP.jl

I would like to know how to include client side certificates when sending requests in HTTP.jl.

In Python, using Requests it would look like this:

requests.get('url', cert=('cert.pem', 'private.key'))

I've unsucessfully tried to:

tlsconfig = MbedTLS.SSLConfig("cert.pem", "private.key")
HTTP.request("GET", "url", sslconfig=tlsconfig)