Extension function to restart a Cocoa application.

NSApplication+Restart.swift

import AppKit

extension NSApplication {

    /// Restarts the application.
    func restart() {
        let process = Process()
        process.launchPath = "/bin/sh"
        process.arguments = ["-c", "sleep 1; open '\(Bundle.main.bundlePath)'"]
        process.launch()
        terminate(nil)
    }
}