# trackLaunchTask(id:onTrackingError:_:) Measures the duration of an asynchronous extended launch task. ``` @MainActor final func trackLaunchTask(id: LaunchTaskID, onTrackingError: ((MetricManager.LaunchTaskError) -> Void)? = nil, _ operation: () async throws(Failure) -> Result) async throws(Failure) -> Result where Failure : Error ``` ## Discussion Use this method to wrap asynchronous work that extends your app’s perceived launch time, such as fetching configuration data, loading initial content, or initializing a local database. Pass a [`LaunchTaskID`](/documentation/MetricKit/LaunchTaskID) and an `async` closure wrapping the work to measure. Measurement begins when the closure starts and ends it when the closure returns, regardless of whether the closure throws. ```swift await manager.trackLaunchTask(id: "initial-data-load") { await loadInitialData() } ``` Pass an `onTrackingError` closure to observe [`MetricManager.LaunchTaskError`](/documentation/MetricKit/MetricManager/LaunchTaskError) values without interrupting the tracked work: ```swift await manager.trackLaunchTask(id: "initial-data-load", onTrackingError: { error in logger.warning("Tracking error: \(error.reason)") }) { await loadInitialData() } ``` To track synchronous launch work instead, use [`trackLaunchTask(id:onTrackingError:_:)`](/documentation/MetricKit/MetricManager/trackLaunchTask(id:onTrackingError:_:)-jnu1). --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)