---
title: "trackLaunchTask(id:onTrackingError:_:)"
framework: metrickit
role: symbol
role_heading: Instance Method
path: "metrickit/metricmanager/tracklaunchtask(id:ontrackingerror:_:)-48k2s"
---

# trackLaunchTask(id:onTrackingError:_:)

Measures the duration of an asynchronous extended launch task.

## Declaration

```swift
@MainActor final func trackLaunchTask<Result, Failure>(id: LaunchTaskID, onTrackingError: ((MetricManager.LaunchTaskError) -> Void)? = nil, _ operation: () async throws(Failure) -> Result) async throws(Failure) -> Result where Failure : Error
```

## Mentioned in

Monitoring app performance with MetricKit

## Discussion

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 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. await manager.trackLaunchTask(id: "initial-data-load") {     await loadInitialData() } Pass an onTrackingError closure to observe MetricManager.LaunchTaskError values without interrupting the tracked work: await manager.trackLaunchTask(id: "initial-data-load", onTrackingError: { error in     logger.warning("Tracking error: \(error.reason)") }) {     await loadInitialData() } This method replaces the paired MXMetricManager.extendLaunchMeasurement(forTaskID:) and MXMetricManager.finishExtendedLaunchMeasurement(forTaskID:) calls. To track synchronous launch work instead, use trackLaunchTask(id:onTrackingError:_:).

## See Also

### Extended launch

- [trackLaunchTask(id:onTrackingError:_:)](metrickit/metricmanager/tracklaunchtask(id:ontrackingerror:_:)-jnu1.md)
- [MetricManager.LaunchTaskError](metrickit/metricmanager/launchtaskerror.md)
- [LaunchTaskID](metrickit/launchtaskid.md)