Method updateMetadataOnDisk tries to move metadata file while it is open. Also, os.Rename is used to replace previous file (if any).

Is your feature request related to a problem? Please describe.
SendableEmail is not Sync at the moment. I think this is because the body of the email is represented by (Box<dyn Read + Send>), which doesn't have the Sync marker trait. Being !Sync prevents sharing &SendableEmail between threads, and sending them to executors that require Sync for such references. It also prevents

Homebrew tap is way out of date, goreleaser should be able to generate a new one. Not sure if it will help with launching Inbucket at boot.

When using default settings, users will experience fewer bugs. So when there are issues, resetting to the default can be a quick fix/workaround. And this can lead to better bug reports.

We did this in Tiki for http://doc.tiki.org/Site-configuration-preferences. I got used to it and miss it in other applications. Basically, it shows user which settings have been modified and lets them reset to