Case2.swift

let imageDatas = await withTaskGroup(of: Data?.self, returning: [Data].self) { group in
  imageIdentifiers.forEach { imageIdentifier in
    group.addTask {
      do {
        return try await ImageProcessor.process(identifier: imageIdentifier)
      } catch {
        return nil
      }
    }
  }
  var results = [Data]()
  for await imageData in group.compactMap({ $0 }) {
    results.append(imageData)
  }
  return results
}