     /// Kitura.start()
     ///```
     public class func start() {
+        serverLock.lock()
         for (server, port) in httpServersAndPorts {
             Log.verbose("Starting an HTTP Server on port \(port)...")
             do {

        let server = FastCGI.createServer()
        server.delegate = delegate
        server.allowPortReuse = allowPortReuse
        fastCGIServersAndPorts.append((server: server, port: port))
        return server
    }


            httpServersAndPorts.removeAll()
            fastCGIServersAndPorts.removeAll()
        }
        serverLock.unlock()
    }

    typealias Port = Int
    private static let serverLock = NSLock()
    internal private(set) static var httpServersAndPorts = [(server: HTTPServer, port: Port)]()
    internal private(set) static var fastCGIServersAndPorts = [(server: FastCGIServer, port: Port)]()
}
