UnenforcedSingleton.swift

class AppDelegate: UIResponder, UIApplicationDelegate {
  
  public enum Shared {
    static public var Heartbeat = HeartbeatManager()
  }
  
}

public class HeartbeatManager {

  public init() {}
  
  func start() {
    print("Running…")
  }
  
}

func accessingSharedHeartbeat() {
  AppDelegate.Shared.Heartbeat.start()
}