Need to double confirm if cpprestsdk supports HTTP proxy server secured by TLS

As I tested, I found that cpprestsdk didn't support HTTP proxy server secured by TLS. If I provided a proxy server URI as https://proxy:443 and captured the traffic, raw HTTP CONNECT was sent instead of TLS handshake.

Need your help to double if HTTP proxy server secured by TLS is in the support list as I couldn't find in public document. Thanks!