---
title: makeAsyncIterator()
framework: realitykit
role: symbol
role_heading: Instance Method
path: realitykit/photogrammetrysession/outputs-swift.struct/makeasynciterator()
---

# makeAsyncIterator()

Creates an asynchronous iterator for the collection.

## Declaration

```swift
func makeAsyncIterator() -> PhotogrammetrySession.Outputs.Iterator
```

## Return Value

Return Value An asynchronous iterator.

## Discussion

Discussion This method creates an asynchronous iterator for the collection. Typically, you won’t call this method. Instead, use a try-await-in loop inside of an async task, which creates an iterator implicitly and waits for the session to publish new PhotogrammetrySession.Output objects, as the following example demonstrates. let waiter = Task {     do {         for try await output in session.outputs {             switch output {                 case .processingComplete:                     // RealityKit has processed all requests.                 case .requestError(let request, let error):                     // Request encountered an error.                 case .requestComplete(let request, let result):                     // RealityKit has finished processing a request.                 case .requestProgress(let request, let fractionComplete):                     // Periodic progress update. Update UI here.                 case requestProgressInfo(let request, let progressInfo):                     // Periodic progress info update.                 case .inputComplete:                     // Ingestion of images is complete and processing begins.                 case .invalidSample(let id, let reason):                     // RealityKit deemed a sample invalid and didn't use it.                 case .skippedSample(let id):                     // RealityKit was unable to use a provided sample.                 case .automaticDownsampling:                     // RealityKit downsampled the input images because of                     // resource constraints.                 case .processingCancelled                     // Processing was canceled.                 @unknown default:                     // Unrecognized output.             }         }     } catch {         print("Output: ERROR = \(String(describing: error))")         // Handle error.     } }