CURLINFO_ACTIVESOCKET(3) on macOS
The text 45649e90c72a, as macOS 10.14.6, macOS 10.14.5, macOS 10.14.4, macOS 10.14.3, macOS 10.14.2, macOS 10.14.1, macOS 10.14, macOS 10.13.6, macOS 10.13.5, macOS 10.13.4, macOS 10.13.3, macOS 10.13.2, macOS 10.13.1, macOS 10.13, macOS 10.12.6 shipped it.
get the active socket