Handle unsuccessful exit status in main.rs.

[apogeeoak]

It may be better to encode an unsuccessful exit status in the Err variant instead of within the Ok variant. io::Result<ExitStatus> can be changed to io::Result<()> with an io::Error being created from ExitStatus. Another option is to create a custom error type. Most code, including main.rs, only checks the Err variant, assuming Ok was successful.

I can work on this change in another pull request if desired. This would be a breaking change but I think would result in more idiomatic code.

[Byron]

Thanks a million!

I can work on this change in another pull request if desired. This would be a breaking change but I think would result in more idiomatic code.

Since the example code didn't manage to get its error handling correct, I think this is where I hope you will find the time to make the fix as suggested in a way that you see fit. If you would prefer a custom error type, implementation by hand should be fine, but so would pulling in quick-error.

My plan would be to create a new patch release once #33 is merged and a major release once the next PR has landed.