Err displays a formatting error message to standard error, appending the error string, and exits with the status code from `exit`, à la err(3).

Errx displays a formatted error message to standard error and exits with the status code from `exit`, à la errx(3).

Pack writes a message to an io.Writer.

Unpack reads a message from an io.Reader.

Warn displays a formatted error message to standard output, appending the error string, à la warn(3).

Before set to 5 minutes; certificates will attempt to auto-update 5 minutes before they expire.