I'm the author of the GitHub issue that the blog links to, and I'd like to thank Stefan for quickly acknowledging the problem and addressing the issue! I try to keep one of our internal applications up to date with the latest libcurl version within a day or two of a release, so we sometimes hit fresh problems while running our battery of tests.

Ironically, our application has also struggled with blocking DNS resolution in the past, so I appreciate the discussion here. In case anyone is interested, here is a quick reference of the different asynchronous DNS resolution methods that you can use in a native code application for some of the most popular platforms:

  - Windows/Xbox: GetAddrInfoExW / GetAddrInfoExCancel
  - macOS/iOS: CFHostStartInfoResolution / CFHostCancelInfoResolution
  - Linux (glibc): getaddrinfo_a / gai_cancel
  - Android: android.net.DnsResolver.query (requires the use of JNI)
  - PS5: proprietary DNS resolver API