An abstraction for a predefined set of functionality, aimed to be ran once, at app startup

AppDelegate.swift

func application(
    _ application: UIApplication,
    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
  ) -> Bool {
    StartupProcessService()
      .execute(process: AppearanceCustomisationStartupProcess())
      .execute(process: AppsFlyerStartupProcess(delegate: self))
      .execute(process: FacebookStartupProcess(application: application, launchOptions: launchOptions))
      .execute(process: GoogleServicesStartupProcess(messagingDelegate: self))
      .execute(process: MixpanelStartupProcess(launchOptions: launchOptions))

    return true
  }

StartupProcess.swift

public protocol StartupProcess {
  func run(completion: @escaping (Bool) -> Void)
}

StartupProcessService.swift

public final class StartupProcessService {
  public init() { }
  
  @discardableResult
  public func execute(process: StartupProcess) -> StartupProcessService {
    process.run { guard $0 else { return } }
    return self
  }
}