How to get git-send-email use a proxy?

Greetings, Git community,

I'm using git-send-email with Git 2.35.1 under system 5.4.72-microsoft-standard-WSL2, x86_64 GNU/Linux.

I am on a system-wide socks5 proxy. Although I set the global .gitconfig to use the socks5 proxy trying to send emails, the connection to the SMTP server seems does not go through the proxy at all.

Other git commands do go through the globally set .gitconfig proxy, git-send-email seems to be an exception.

So I'm wondering if there needs to be a code change in 'git-send-email.perl' to run the connection through a proxy, or I just need to tune the setting to accomplish this?