curl_easy_pause(3) on macOS

The text e3aab25a543f, as Mac OS X 10.7.5, Mac OS X 10.7.4, Mac OS X 10.7.3, Mac OS X 10.7.2, Mac OS X 10.7.1, Mac OS X 10.7 shipped it.

pause and unpause a connection

curl_easy_pause(3) on macOS now