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We're building a thin abstraction layer around downloading HLS content using AVFoundation. We'd like to notify a client when an error occurs so that there's a chance to update a UI appropriately, but the urlSession(_:task:didCompleteWithError:) never gets called even when going to airplay mode right in the middle of a download process – neither immediately, nor after like five minute delay. The only moment it does get called is when a download task gets cancelled. Trying to observe AVAssetDownloadTask's state property also yielded no results. Is it so by design or am I missing something? Thanks.