The Fatal method is calling os.Exit(1) regardless of a message. This isn't the best UX choice. The POSIX return code could be used for quick assessment about a process failure. When the retcode is always equal 1 for any error, this can't be utilized.

Tools like Docker or Kubernetes report back the return code of the process. By using a deterministic algorithm to calculate the POSIX return code, a quick debugging is possible. Users could indicate if the process is failing because of the same reason, without looking into logs.

The best would be to rely on Fatal's message or on an error object if it's attached as a Field.