Use `failure` For Errors

[AzureMarker]

failure is a crate for error management. It allows you to easily create errors with all the functionality you need, including backtraces, associated data, and error messages. Its biggest strength though is that these errors can be used alongside every other error, so you can set the output of a function to Result<T, failure::Error> and every kind of error can be thrown without losing information like the backtrace and cause.