Observe Screen Locking in macOS

In Quids, similar to 1Password, we lock the app when your Mac locks.

There are two notifications sent via the DistributedNotificationCenter. One when the screen is locked and the other when it is unlocked. I couldn't find any predefined variables so created this Notification.Name extension:

internal extension Notification.Name
{
    static let screenIsLocked = Notification.Name("com.apple.screenIsLocked")
    static let screenIsUnlocked = Notification.Name("com.apple.screenIsUnlocked")
}

Then all that is left to do is register an object as an observer:

DistributedNotificationCenter.default().addObserver(self, selector: #selector(...), name: Notification.Name.screenIsLocked, object: nil)